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Diffstat (limited to '')
| -rw-r--r-- | debian/local/apport/source_mdadm.py | 60 | ||||
| -rwxr-xr-x | debian/local/bin/checkarray | 221 | ||||
| -rwxr-xr-x | debian/local/bin/mkconf | 104 | ||||
| -rw-r--r-- | debian/local/doc/FAQ | 669 | ||||
| -rw-r--r-- | debian/local/doc/README.checkarray | 33 | ||||
| -rw-r--r-- | debian/local/doc/README.recipes | 168 | ||||
| -rwxr-xr-x | debian/local/initramfs-tools/local-block/mdadm | 61 | ||||
| -rwxr-xr-x | debian/local/initramfs-tools/local-bottom/mdadm | 3 | ||||
| -rwxr-xr-x | debian/local/reportbug/script | 219 |
9 files changed, 1538 insertions, 0 deletions
diff --git a/debian/local/apport/source_mdadm.py b/debian/local/apport/source_mdadm.py new file mode 100644 index 0000000..0aad41b --- /dev/null +++ b/debian/local/apport/source_mdadm.py @@ -0,0 +1,60 @@ +'''apport package hook for mdadm + +(c) 2009-2016 Canonical Ltd. +Author: Steve Beattie <sbeattie@ubuntu.com> + +Based on the ideas in debian's /usr/share/bug/mdadm/script +''' + +from apport.hookutils import attach_file, attach_file_if_exists, attach_hardware, path_to_key, command_output +import os +import re +import glob +import gzip +import subprocess +import sys + + +def get_initrd_files(pattern): + '''Extract listing of files from the current initrd which match a regex. + + pattern should be a "re" object. ''' + + (_, _, release, _, _) = os.uname() + try: + fd = gzip.GzipFile('/boot/initrd.img-' + release, 'rb') + # universal_newlines needs to be False here as we're passing + # binary data from gzip into cpio, which means we'll need to + # decode the bytes into strings later when reading the output + cpio = subprocess.Popen(['cpio', '-t'], close_fds=True, stderr=subprocess.STDOUT, + stdin=subprocess.PIPE, stdout=subprocess.PIPE, + universal_newlines=False) + except OSError as e: + return 'Error: ' + str(e) + + out = cpio.communicate(fd.read())[0].decode(sys.stdout.encoding, errors='replace') + if cpio.returncode != 0: + return 'Error: command %s failed with exit code %i %' % ( + 'cpio', cpio.returncode, out) + + lines = ''.join([l for l in out.splitlines(True) if pattern.search(l)]) + return lines + + +def add_info(report): + attach_hardware(report) + attach_file(report, '/proc/mounts', 'ProcMounts') + attach_file_if_exists(report, '/etc/mdadm/mdadm.conf', 'mdadm.conf') + attach_file(report, '/proc/mdstat', 'ProcMDstat') + attach_file(report, '/proc/partitions', 'ProcPartitions') + attach_file(report, '/etc/blkid.tab', 'etc.blkid.tab') + attach_file_if_exists(report, '/boot/grub/menu.lst', 'GrubMenu.lst') + attach_file_if_exists(report, '/boot/grub/grub.cfg', 'Grub.cfg') + attach_file_if_exists(report, '/etc/lilo.conf', 'lilo.conf') + + devices = glob.glob("/dev/[hs]d*") + for dev in devices: + report['MDadmExamine' + path_to_key(dev)] = command_output(['/sbin/mdadm', '-E', dev]) + + initrd_re = re.compile('md[a/]') + report['initrd.files'] = get_initrd_files(initrd_re) diff --git a/debian/local/bin/checkarray b/debian/local/bin/checkarray new file mode 100755 index 0000000..2fb7ee7 --- /dev/null +++ b/debian/local/bin/checkarray @@ -0,0 +1,221 @@ +#!/bin/sh +# +# checkarray -- initiates a check run of an MD array's redundancy information. +# +# Copyright © martin f. krafft <madduck@debian.org> +# distributed under the terms of the Artistic Licence 2.0 +# +set -eu + +PROGNAME=${0##*/} + +about() +{ + echo "\ +$PROGNAME -- MD array (RAID) redundancy checker tool +Copyright © martin f. krafft <madduck@debian.org> +Released under the terms of the Artistic Licence 2.0" +} + +usage() +{ + about + echo " +Usage: $PROGNAME [options] [arrays] + +Valid options are: + -a|--all check all assembled arrays (ignores arrays in command line). + -s|--status print redundancy check status of devices. + -x|--cancel queue a request to cancel a running redundancy check. + -r|--repair repair instead of check + -i|--idle perform check in a lowest scheduling class (idle) + -l|--slow perform check in a lower-than-standard scheduling class + -f|--fast perform check in higher-than-standard scheduling class + --realtime perform check in real-time scheduling class (DANGEROUS!) + -c|--cron honour AUTOCHECK setting in /etc/default/mdadm. + -q|--quiet suppress informational messages + (use twice to suppress error messages too). + -h|--help show this output. + -V|--version show version information. + +Examples: + $PROGNAME --all --idle + $PROGNAME --quiet /dev/md[123] + $PROGNAME -sa + $PROGNAME -x --all + +Devices can be specified in almost any format. The following are equivalent: + /dev/md0, md0, /dev/md/0, /sys/block/md0 + +You can also control the status of a check/repair with /proc/mdstat file." +} + +SHORTOPTS=achVqQsxrilf +LONGOPTS=all,cron,help,version,quiet,real-quiet,status,cancel,repair,idle,slow,fast,realtime + +eval set -- $(getopt -o $SHORTOPTS -l $LONGOPTS -n $PROGNAME -- "$@") + +arrays='' +cron=0 +all=0 +quiet=0 +status=0 +action=check +ionice= + +for opt in $@; do + case "$opt" in + -a|--all) all=1;; + -s|--status) action=status;; + -x|--cancel) action=idle;; + -r|--repair) action=repair;; + -i|--idle) ionice=idle;; + -l|--slow) ionice=low;; + -f|--fast) ionice=high;; + --realtime) ionice=realtime;; + -c|--cron) cron=1;; + -q|--quiet) quiet=$(($quiet+1));; + -Q|--real-quiet) quiet=$(($quiet+2));; # for compatibility + -h|--help) usage; exit 0;; + -V|--version) about; exit 0;; + /dev/md/*|md/*) arrays="${arrays:+$arrays }md${opt#*md/}";; + /dev/md*|md*) arrays="${arrays:+$arrays }${opt#/dev/}";; + /sys/block/md*) arrays="${arrays:+$arrays }${opt#/sys/block/}";; + --) :;; + *) echo "$PROGNAME: E: invalid option: $opt. Try --help." >&2; exit 1;; + esac +done + +is_true() +{ + case "${1:-}" in + [Yy]es|[Yy]|1|[Tt]rue|[Tt]) return 0;; + *) return 1; + esac +} + +DEBIANCONFIG=/etc/default/mdadm +[ -r $DEBIANCONFIG ] && . $DEBIANCONFIG +if [ $cron = 1 ] && ! is_true ${AUTOCHECK:-false}; then + [ $quiet -lt 1 ] && echo "$PROGNAME: I: disabled in $DEBIANCONFIG ." >&2 + exit 0 +fi + +if [ ! -f /proc/mdstat ]; then + [ $quiet -lt 2 ] && echo "$PROGNAME: E: MD subsystem not loaded, or /proc unavailable." >&2 + exit 2 +fi + +if [ ! -d /sys/block ]; then + [ $quiet -lt 2 ] && echo "$PROGNAME: E: /sys filesystem not available." >&2 + exit 7 +fi + +if [ -z "$(ls /sys/block/md* 2>/dev/null)" ]; then + if [ $quiet -lt 2 ] && [ $cron != 1 ]; then + echo "$PROGNAME: W: no active MD arrays found." >&2 + echo "$PROGNAME: W: (maybe uninstall the mdadm package?)" >&2 + fi + exit 0 +fi + +if [ -z "$(ls /sys/block/md*/md/level 2>/dev/null)" ]; then + [ $quiet -lt 2 ] && echo "$PROGNAME: E: kernel too old, no support for redundancy checks." >&2 + exit 6 +fi + +if ! egrep -q '^raid([1456]|10)$' /sys/block/md*/md/level 2>/dev/null; then + [ $quiet -lt 1 ] && echo "$PROGNAME: I: no redundant arrays present; skipping checks..." >&2 + exit 0 +fi + +if [ -z "$(ls /sys/block/md*/md/sync_action 2>/dev/null)" ]; then + [ $quiet -lt 2 ] && echo "$PROGNAME: E: no kernel support for redundancy checks." >&2 + exit 3 +fi + +[ $all = 1 ] && arrays="$(ls -d1 /sys/block/md* | cut -d/ -f4)" + +for array in $arrays; do + MDBASE=/sys/block/$array/md + + if [ ! -e $MDBASE/sync_action ]; then + [ $quiet -lt 1 ] && echo "$PROGNAME: I: skipping non-redundant array $array." >&2 + continue + fi + + cur_status="$(cat $MDBASE/sync_action)" + + if [ $action = status ]; then + echo "$array: $cur_status" + continue + fi + + if [ ! -w $MDBASE/sync_action ]; then + [ $quiet -lt 2 ] && echo "$PROGNAME: E: $MDBASE/sync_action not writeable." >&2 + exit 4 + fi + + if [ "$(cat $MDBASE/array_state)" = 'read-auto' ]; then + [ $quiet -lt 1 ] && echo "$PROGNAME: W: array $array in auto-read-only state, skipping..." >&2 + continue + fi + + case "$action" in + idle) + echo $action > $MDBASE/sync_action + [ $quiet -lt 1 ] && echo "$PROGNAME: I: cancel request queued for array $array." >&2 + ;; + + check|repair) + if [ "$cur_status" != idle ]; then + [ $quiet -lt 2 ] && echo "$PROGNAME: W: array $array not idle, skipping..." >&2 + continue + fi + + # check if the array created recently and skip test if it is + created=$(mdadm --detail /dev/$array 2>/dev/null | + sed -n 's/.*Creation Time *://p' ) + if [ -n "$created" ]; then + created=$(date +%s -d "$created" 2>/dev/null) + fi + if [ -n "$created" ]; then + now=$(date +%s) + if [ "$created" -lt "$now" -a \ + "$created" -gt "$(($now - 14 * 24 * 60 * 60))" ]; then + [ $quiet -lt 2 ] && echo "$PROGNAME: I: array $array created recently, skipping..." >&2 + continue + fi + fi + + # queue request for the array. The kernel will make sure that these requests + # are properly queued so as to not kill one of the arrays. + echo $action > $MDBASE/sync_action + [ $quiet -lt 1 ] && echo "$PROGNAME: I: $action queued for array $array." >&2 + + case "$ionice" in + idle) ioarg='-c3'; renice=15;; + low) ioarg='-c2 -n7'; renice=5;; + high) ioarg='-c2 -n0'; renice=0;; + realtime) ioarg='-c1 -n4'; renice=-5;; + *) continue;; + esac + + resync_pid= wait=5 + while [ $wait -gt 0 ]; do + wait=$((wait - 1)) + resync_pid=$(ps -ef | awk -v dev=$array 'BEGIN { pattern = "^\\[" dev "_resync]$" } $8 ~ pattern { print $2 }') + if [ -n "$resync_pid" ]; then + [ $quiet -lt 1 ] && echo "$PROGNAME: I: selecting $ionice I/O scheduling class and $renice niceness for resync of $array." >&2 + ionice -p "$resync_pid" $ioarg 2>/dev/null || : + renice -n $renice -p "$resync_pid" 1>/dev/null 2>&1 || : + break + fi + sleep 1 + done + ;; + esac + +done + +exit 0 diff --git a/debian/local/bin/mkconf b/debian/local/bin/mkconf new file mode 100755 index 0000000..4dd09b1 --- /dev/null +++ b/debian/local/bin/mkconf @@ -0,0 +1,104 @@ +#!/bin/sh +# +# mkconf -- outputs valid mdadm.conf contents for the local system +# +# Copyright © martin f. krafft <madduck@madduck.net> +# distributed under the terms of the Artistic Licence 2.0 +# +set -eu + +ME="${0##*/}" +MDADM=/sbin/mdadm +DEBIANCONFIG=/etc/default/mdadm +CONFIG=/etc/mdadm/mdadm.conf + +# initialise config variables in case the environment leaks +MAILADDR= DEVICE= HOMEHOST= PROGRAM= + +test -r $DEBIANCONFIG && . $DEBIANCONFIG + +if [ -n "${MDADM_MAILADDR__:-}" ]; then + # honour MAILADDR from the environment (from postinst) + MAILADDR="$MDADM_MAILADDR__" +else + # preserve existing MAILADDR + MAILADDR="$(sed -ne 's/^MAILADDR //p' $CONFIG 2>/dev/null)" || : +fi + +# save existing values as defaults +if [ -r "$CONFIG" ]; then + DEVICE="$(sed -ne 's/^DEVICE //p' $CONFIG)" + HOMEHOST="$(sed -ne 's/^HOMEHOST //p' $CONFIG)" + PROGRAM="$(sed -ne 's/^PROGRAM //p' $CONFIG)" +fi + +[ "${1:-}" = force-generate ] && rm -f $CONFIG +case "${1:-}" in + generate|force-generate) + [ -n "${2:-}" ] && CONFIG=$2 + # only barf if the config file specifies anything else than MAILADDR + if egrep -qv '^(MAILADDR.*|#.*|)$' $CONFIG 2>/dev/null; then + echo "E: $ME: $CONFIG already exists." >&2 + exit 255 + fi + + mkdir --parent ${CONFIG%/*} + exec >$CONFIG + ;; +esac + +cat <<_eof +# mdadm.conf +# +# !NB! Run update-initramfs -u after updating this file. +# !NB! This will ensure that initramfs has an uptodate copy. +# +# Please refer to mdadm.conf(5) for information about this file. +# + +# by default (built-in), scan all partitions (/proc/partitions) and all +# containers for MD superblocks. alternatively, specify devices to scan, using +# wildcards if desired. +#DEVICE ${DEVICE:-partitions containers} + +# automatically tag new arrays as belonging to the local system +HOMEHOST ${HOMEHOST:-<system>} + +# instruct the monitoring daemon where to send mail alerts +MAILADDR ${MAILADDR:-root} + +_eof + +if [ -n "${PROGRAM:-}" ]; then + cat <<-_eof + # program to run when mdadm monitor detects potentially interesting events + PROGRAM ${PROGRAM} + + _eof +fi + +error=0 +if [ ! -r /proc/mdstat ]; then + echo W: $ME: MD subsystem is not loaded, thus I cannot scan for arrays. >&2 + error=1 +elif [ ! -r /proc/partitions ]; then + echo W: $ME: /proc/partitions cannot be read, thus I cannot scan for arrays. >&2 + error=2 +else + echo "# definitions of existing MD arrays" + if ! $MDADM --examine --scan --config=partitions; then + error=$(($? + 128)) + echo W: $ME: failed to scan for partitions. >&2 + echo "### WARNING: scan failed." + else + echo + fi +fi + +if [ -z "${SOURCE_DATE_EPOCH:-}" ]; then + echo "# This configuration was auto-generated on $(date -R) by mkconf" +else + echo "# This configuration was auto-generated on $(date -R --utc -d@$SOURCE_DATE_EPOCH) by mkconf" +fi + +exit $error diff --git a/debian/local/doc/FAQ b/debian/local/doc/FAQ new file mode 100644 index 0000000..40e0aba --- /dev/null +++ b/debian/local/doc/FAQ @@ -0,0 +1,669 @@ +Frequently asked questions -- Debian mdadm +========================================== + +Also see /usr/share/doc/mdadm/README.recipes.gz . + +The latest version of this FAQ is available here: + http://anonscm.debian.org/gitweb/?p=pkg-mdadm/mdadm.git;a=blob_plain;f=debian/FAQ;hb=HEAD + +0. What does MD stand for? +~~~~~~~~~~~~~~~~~~~~~~~~~~ + MD is an abbreviation for "multiple device" (also often called "multi- + disk"). The Linux MD implementation implements various strategies for + combining multiple (typically but not necessarily physical) block devices + into single logical ones. The most common use case is commonly known as + "Software RAID". Linux supports RAID levels 1, 4, 5, 6 and 10 as well + as the "pseudo" RAID level 0. + In addition, the MD implementation covers linear and multipath + configurations. + + Most people refer to MD as RAID. Since the original name of the RAID + configuration software is "md"adm, I chose to use MD consistently instead. + +1. How do I overwrite ("zero") the superblock? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + mdadm --zero-superblock /dev/sdXY + + Note that this is a destructive operation. It does not actually delete any + data, but the device will have lost its "authority". You cannot assemble the + array with it anymore and if you add the device to another array, the + synchronisation process *will* *overwrite* all data on the device. + + Nevertheless, sometimes it is necessary to zero the superblock: + + - If you want ot re-use a device (e.g. a HDD or SSD) that has been part of an + array (with an different superblock version and/or location) in another one. + In this case you zero the superblock before you assemble the array or add + the device to a new array. + + - If you are trying to prevent a device from being recognised as part of an + array. Say for instance you are trying to change an array spanning sd[ab]1 + to sd[bc]1 (maybe because sda is failing or too slow), then automatic + (scan) assembly will still recognise sda1 as a valid device. You can limit + the devices to scan with the DEVICE keyword in the configuration file, but + this may not be what you want. Instead, zeroing the superblock will + (permanently) prevent a device from being considered as part of an array. + + WARNING: Depending on which superblock version you use, it won't work to just + overwrite the first few MiBs of the block device with 0x0 (e.g. via + dd), since the superblock may be at other locations (especially the + end of the device). + Therefore always use mdadm --zero-superblock . + +2. How do I change the preferred minor of an MD array (RAID)? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + See item 12 in /usr/share/doc/mdadm/README.recipes.gz and read the mdadm(8) + manpage (search for 'preferred'). + +3. How does mdadm determine which /dev/mdX or /dev/md/X to use? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + The logic used by mdadm to determine the device node name in the mdadm + --examine output (which is used to generate mdadm.conf) depends on several + factors. Here's how mdadm determines it: + + It first checks the superblock version of a given array (or each array in + turn when iterating all of them). Run + + mdadm --detail /dev/mdX | sed -ne 's,.*Version : ,,p' + + to determine the superblock version of a running array, or + + mdadm --examine /dev/sdXY | sed -ne 's,.*Version : ,,p' + + to determine the superblock version from a component device of an array. + + Version 0 superblocks (00.90.XX) + '''''''''''''''''''''''''''''''' + You need to know the preferred minor number stored in the superblock, + so run either of + + mdadm --detail /dev/mdX | sed -ne 's,.*Preferred Minor : ,,p' + mdadm --examine /dev/sdXY | sed -ne 's,.*Preferred Minor : ,,p' + + Let's call the resulting number MINOR. Also see FAQ 2 further up. + + Given MINOR, mdadm will output /dev/md<MINOR> if the device node + /dev/md<MINOR> exists. + Otherwise, it outputs /dev/md/<MINOR> + + Version 1 superblocks (01.XX.XX) + '''''''''''''''''''''''''''''''' + Version 1 superblocks actually seem to ignore preferred minors and instead + use the value of the name field in the superblock. Unless specified + explicitly during creation (-N|--name) the name is determined from the + device name used, using the following regexp: 's,/dev/md/?(.*),$1,', thus: + + /dev/md0 -> 0 + /dev/md/0 -> 0 + /dev/md_d0 -> _d0 (d0 in later versions) + /dev/md/d0 -> d0 + /dev/md/name -> name + (/dev/name does not seem to work) + + mdadm will append the name to '/dev/md/', so it will always output device + names under the /dev/md/ directory. Newer versions can create a symlink + from /dev/mdX. See the symlinks option in mdadm.con(5) and mdadm(8). + + If you want to change the name, you can do so during assembly: + + mdadm -A -U name -N newname /dev/mdX /dev/sd[abc]X + + I know this all sounds inconsistent and upstream has some work to do. + We're on it. + +4. Which RAID level should I use? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + Many people seem to prefer RAID4/5/6 because it makes more efficient use of + space. For example, if you have devices of size X, then in order to get 2X + storage, you need 3 devices for RAID5, but 4 if you use RAID10 or RAID1+ (or + RAID6). + + This gain in usable space comes at a price: performance; RAID1/10 can be up + to four times faster than RAID4/5/6. + + At the same time, however, RAID4/5/6 provide somewhat better redundancy in + the event of two failing devices. In a RAID10 configuration, if one device is + already dead, the RAID can only survive if any of the two devices in the other + RAID1 array fails, but not if the second device in the degraded RAID1 array + fails (see next item, 4b). A RAID6 across four devices can cope with any two + devices failing. However, RAID6 is noticeably slower than RAID5. RAID5 and + RAID4 do not differ much, but can only handle single-device failures. + + If you can afford the extra devices (storage *is* cheap these days), I suggest + RAID1/10 over RAID4/5/6. If you don't care about performance but need as + much space as possible, go with RAID4/5/6, but make sure to have backups. + Heck, make sure to have backups whatever you do. + + Let it be said, however, that I thoroughly regret putting my primary + workstation on RAID5. Anything device-intensive brings the system to its + knees; I will have to migrate to RAID10 at one point. + + Please also consult /usr/share/doc/mdadm/RAID5_versus_RAID10.txt.gz, + https://en.wikipedia.org/wiki/Standard_RAID_levels and perhaps even + https://en.wikipedia.org/wiki/Non-standard_RAID_levels . + +4b. Can a 4-device RAID10 survive two device failures? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + I am assuming that you are talking about a setup with two copies of each + block, so --layout=near2/far2/offset2: + + In two thirds of the cases, yes[0], and it does not matter which layout you + use. When you assemble 4 devices into a RAID10, you essentially stripe a RAID0 + across two RAID1, so the four devices A,B,C,D become two pairs: A,B and C,D. + If A fails, the RAID10 can only survive if the second failing device is either + C or D; if B fails, your array is dead. + + Thus, if you see a device failing, replace it as soon as possible! + + If you need to handle two failing devices out of a set of four, you have to + use RAID6, or store more than two copies of each block (see the --layout + option in the mdadm(8) manpage). + + See also question 18 further down. + + [0] It's actually (n-2)/(n-1), where n is the number of devices. I am not + a mathematician, see http://aput.net/~jheiss/raid10/, which gives the + chance of *failure* as 1/(n-1), so the chance of success is 1-1/(n-1), or + (n-2)/(n-1), or 2/3 in the four device example. + (Thanks to Per Olofsson for clarifying this in #493577). + +5. How to convert RAID5 to RAID10? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + To convert 3 device RAID5 to RAID10, you need a spare device (either a hot + spare, fourth device in the array, or a new one). Then you remove the spare + and one of the three devices from the RAID5, create a degraded RAID10 across + them, create the filesystem and copy the data (or do a raw copy), then add the + other two devices to the new RAID10. However, mdadm cannot assemble a RAID10 + with 50% missing devices the way you might like it: + + mdadm --create -l 10 -n4 -pn2 /dev/md1 /dev/sd[cd] missing missing + + For reasons that may be answered by question 20 further down, mdadm actually + cares about the order of devices you give it. If you intersperse the "missing" + keywords with the physical devices, it should work: + + mdadm --create -l 10 -n4 -pn2 /dev/md1 /dev/sdc missing /dev/sdd missing + + or even + + mdadm --create -l 10 -n4 -pn2 /dev/md1 missing /dev/sd[cd] missing + + Also see item (4b) further up, and this thread: + http://thread.gmane.org/gmane.linux.raid/13469/focus=13472 + +6. What is the difference between RAID1+0 and RAID10? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + RAID1+0 is a form of RAID in which a RAID0 is striped across two RAID1 + arrays. To assemble it, you create two RAID1 arrays and then create a RAID0 + array with the two md arrays. + + The Linux kernel provides the RAID10 level to do pretty much exactly the + same for you, but with greater flexibility (and somewhat improved + performance). While RAID1+0 makes sense with 4 devices, RAID10 can be + configured to work with only 3 devices. Also, RAID10 has a little less + overhead than RAID1+0, which has data pass the md layer twice. + + I prefer RAID10 over RAID1+0. + +6b. What's the difference between RAID1+0 and RAID0+1? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + In short: RAID1+0 concatenates two mirrored arrays while RAID0+1 mirrors two + concatenated arrays. However, the two are also often switched. + + The linux MD driver supports RAID10, which is equivalent to the above + RAID1+0 definition. + + RAID1+0/10 has a greater chance to survive two device failures, its + performance suffers less when in degraded state, and it resyncs faster after + replacing a failed device. + + See http://aput.net/~jheiss/raid10/ for more details. + +7. Which RAID10 layout scheme should I use +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + RAID10 gives you the choice between three ways of laying out chunks on the + devices: near, far and offset. + + The examples below explain the chunk distribution for each of these layouts + with 2 copies per chunk, using either an even number of devices (fewer than 4) + or an odd number (fewer than 5). + + For simplicity we assume that the chunk size matches the block size of the + underlying devices and also the RAID10 device exported by the kernel + (e.g. /dev/md/name). The chunk numbers map therefore directly to the block + addresses in the exported RAID10 device. + + The decimal numbers below (0, 1, 2, …) are the RAID10 chunks. Due to the + foregoing assumption they are also the block addresses in the exported RAID10 + device. Identical numbers refer to copies of a chunk or block, but on different + underlying devices. The hexadecimal numbers (0x00, 0x01, 0x02, …) refer to the + block addresses in the underlying devices. + + "near" layout with 2 copies per chunk (--layout=n2): + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + The chunk copies are placed "as close to each other as possible". + + With an even number of devices, they lie at the same offset on the each device. + It is a classic RAID1+0 setup, i.e. two groups of mirrored devices, with both + forming a striped RAID0. + + device1 device2 device3 device4 device1 device2 device3 device4 device5 + ─────── ─────── ─────── ─────── ─────── ─────── ─────── ─────── ─────── + 0 0 1 1 0x00 0 0 1 1 2 + 2 2 3 3 0x01 2 3 3 4 4 + ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ + ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ + ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ + 254 254 255 255 0x80 317 318 318 319 319 + ╰──────┬──────╯ ╰──────┬──────╯ + RAID1 RAID1 + ╰──────────────┬──────────────╯ + RAID0 + + "far" layout with 2 copies per chunk (--layout=f2): + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + The chunk copies are placed "as far from each other as possible". + + Here, a complete sequence of chunks is striped over all devices. Then a second + sequence of chunks is placed next to them. More copies are added as the number + 2 goes up. + + It is undesirable, however, to place copies of the same chunks on the same + devices. That is prevented by a cyclic permutation of each such stripe. + + device1 device2 device3 device4 device1 device2 device3 device4 device5 + ─────── ─────── ─────── ─────── ─────── ─────── ─────── ─────── ─────── + 0 1 2 3 0x00 0 1 2 3 4 ╮ + 4 5 6 7 0x01 5 6 7 8 9 ├ ▒ + ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ┆ + ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ┆ + ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ┆ + 252 253 254 255 0x40 315 316 317 318 319 ╯ + 3 0 1 2 0x41 4 0 1 2 3 ╮ + 7 4 5 6 0x42 9 5 6 7 8 ├ ▒ₚ + ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ┆ + ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ┆ + ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ┆ + 255 252 253 254 0x80 319 315 316 317 318 ╯ + + Each ▒ in the diagram represents a complete sequence of chunks. ▒ₚ is a cyclic + permutation. + + A major advantage of the "far" layout is that sequential reads can be spread + out over different devices, which makes the setup similar to RAID0 in terms of + speed. For writes, there is a cost of seeking. They are substantially slower. + + "offset" layout with 2 copies per chunk (--layout=o2): + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + Here, a number of consecutive chunks are bundled on each device during the + striping operation. The number of consecutive chunks equals the number of + devices. Next, a copy of the same chunks is striped in a different pattern. + More copies are added as the number 2 goes up. + + A cyclic permutation in the pattern prevents copies of the same chunks + landing on the same devices. + + device1 device2 device3 device4 device1 device2 device3 device4 device5 + ─────── ─────── ─────── ─────── ─────── ─────── ─────── ─────── ─────── + 0 1 2 3 0x00 0 1 2 3 4 ) AA + 3 0 1 2 0x01 4 0 1 2 3 ) AAₚ + 4 5 6 7 0x02 5 6 7 8 9 ) AB + 7 4 5 6 0x03 9 5 6 7 8 ) ABₚ + ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ) ⋯ + ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ + ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ) ⋯ + 251 252 253 254 0x79 314 315 316 317 318 ) EX + 254 251 252 253 0x80 318 314 315 316 317 ) EXₚ + + With AA, AB, …, AZ, BA, … being the sets of consecutive chunks and + AAₚ, ABₚ, …, AZₚ, BAₚ, … their cyclic permutations. + + The read characteristics are probably similar to the "far" layout when a + suitably large chunk size is chosen, but with less seeking for writes. + + Upstream and the Debian maintainer do not understand all the nuances and + implications. The "offset" layout was only added because the Common + RAID Data Disk Format (DDF) supports it, and standard compliance is our + goal. + + See the md(4) manpage for more details. + +8. (One of) my RAID arrays is busy and cannot be stopped. What gives? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + It is perfectly normal for mdadm to report the array with the root + filesystem to be busy on shutdown. The reason for this is that the root + filesystem must be mounted to be able to stop the array (or otherwise + /sbin/mdadm does not exist), but to stop the array, the root filesystem + cannot be mounted. Catch 22. The kernel actually stops the array just before + halting, so it's all well. + + If mdadm cannot stop other arrays on your system, check that these arrays + aren't used anymore. Common causes for busy/locked arrays are: + + * The array contains a mounted filesystem (check the `mount' output) + * The array is used as a swap backend (check /proc/swaps) + * The array is used by the device-mapper (check with `dmsetup') + * LVM + * dm-crypt + * EVMS + * The array contains a swap partition used for suspend-to-ram + (check /etc/initramfs-tools/conf.d/resume) + * The array is used by a process (check with `lsof') + +9. Should I use RAID0 (or linear)? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + No. Unless you know what you're doing and keep backups, or use it for data + that can be lost. + +9b. Why not? +~~~~~~~~~~~~ + RAID0 has zero redundancy. If you stripe a RAID0 across X devices, you + increase the likelyhood of complete loss of the filesystem by a factor of X. + + The same applies to LVM by the way (when LVs are placed over X PVs). + + If you want/must used LVM or RAID0, stripe it across RAID1 arrays + (RAID10/RAID1+0, or LVM on RAID1), and keep backups! + +10. Can I cancel a running array check (checkarray)? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + See the -x option in the `/usr/share/mdadm/checkarray --help` output. + +11. mdadm warns about duplicate/similar superblocks; what gives? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + In certain configurations, especially if your last partition extends all the + way to the end of the device, mdadm may display a warning like: + + mdadm: WARNING /dev/sdXY and /dev/sdX appear to have very similar + superblocks. If they are really different, please --zero the superblock on + one. If they are the same or overlap, please remove one from the DEVICE + list in mdadm.conf. + + There are two ways to solve this: + + (a) recreate the arrays with version-1 superblocks, which is not always an + option -- you cannot yet upgrade version-0 to version-1 superblocks for + existing arrays. + + (b) instead of 'DEVICE partitions', list exactly those devices that are + components of MD arrays on your system. So istead of: + + DEVICE partitions + + for example: + + DEVICE /dev/sd[ab]* /dev/sdc[123] + +12. mdadm -E / mkconf report different arrays with the same device + name / minor number. What gives? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + In almost all cases, mdadm updates the super-minor field in an array's + superblock when assembling the array. It does *not* do this for RAID0 + arrays. Thus, you may end up seeing something like this when you run + mdadm -E or mkconf: + + ARRAY /dev/md0 level=raid0 num-devices=2 UUID=abcd... + ARRAY /dev/md0 level=raid1 num-devices=2 UUID=dcba... + + Note how the two arrays have different UUIDs but both appear as /dev/md0. + + The solution in this case is to explicitly tell mdadm to update the + superblock of the RAID0 array. Assuming that the RAID0 array in the above + example should really be /dev/md1: + + mdadm --stop /dev/md1 + mdadm --assemble --update=super-minor --uuid=abcd... /dev/md1 + + See question 2 of this FAQ, and also http://bugs.debian.org/386315 and + recipe #12 in README.recipes . + +13. Can a MD array be partitioned? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + Since kernel 2.6.28, MD arrays can be partitioned like any other block + device. + + Prior to 2.6.28, for a MD array to be able to hold partitions, it must be + created as a "partitionable array", using the configuration auto=part on the + command line or in the configuration file, or by using the standard naming + scheme (md_d* or md/d*) for partitionable arrays: + + mdadm --create --auto=yes ... /dev/md_d0 ... + # see mdadm(8) manpage about the values of the --auto keyword + +14. When would I partition an array? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + This answer by Doug Ledford is shamelessly adapted from [0] (with + permission): + + First, not all MD types make sense to be split up, e.g. multipath. For + those types, when a device fails, the *entire* device is considered to have + failed, but with different arrays you won't switch over to the next path + until each MD array has attempted to access the bad path. This can have + obvious bad consequences for certain array types that do automatic + failover from one port to another (you can end up getting the array in + a loop of switching ports repeatedly to satisfy the fact that one array + failed over during a path down, then the path came back up, and another + array stayed on the old path because it didn't send any commands during + the path down time period). + + Second, convenience. Assume you have a 6 device RAID5 array. If a device + fails and you are using a partitioned MD array, then all the partitions on + the device will already be handled without using that device. No need to + manually fail any still active array members from other arrays. + + Third, safety. Again with the RAID5 array. If you use multiple arrays on + a single device, and that device fails, but it only failed on one array, then + you now need to manually fail that device from the other arrays before + shutting down or hot swapping the device. Generally speaking, that's not + a big deal, but people do occasionally have fat finger syndrome and this + is a good opportunity for someone to accidentally fail the wrong device, and + when you then go to remove the device you create a two device failure instead + of one and now you are in real trouble. + + Forth, to respond to what you wrote about independent of each other -- + part of the reason why you partition. I would argue that's not true. If + your goal is to salvage as much use from a failing device as possible, then + OK. But, generally speaking, people that have something of value on their + devices don't want to salvage any part of a failing device, they want that + device gone and replaced immediately. There simply is little to no value in + an already malfunctioning device. They're too cheap and the data stored on + them too valuable to risk loosing something in an effort to further + utilize broken hardware. This of course is written with the understanding + that the latest MD RAID code will do read error rewrites to compensate for + minor device issues, so anything that will throw a device out of an array is + more than just a minor sector glitch. + + [0] http://thread.gmane.org/gmane.linux.raid/13594/focus=13597 + +15. How can I start a dirty degraded array? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + A degraded array (e.g. a RAID5 with only two devices) that has not been + properly stopped cannot be assembled just like that; mdadm will refuse and + complain about a "dirty degraded array", for good reasons. + + The solution might be to force-assemble it, and then to start it. Please see + recipes 4 and 4b of /usr/share/doc/mdadm/README.recipes.gz and make sure you + know what you're doing. + +16. How can I influence the speed with which an array is resynchronised? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + For each array, the MD subsystem exports parameters governing the + synchronisation speed via sysfs. The values are in kB/sec. + + /sys/block/mdX/md/sync_speed -- the current speed + /sys/block/mdX/md/sync_speed_max -- the maximum speed + /sys/block/mdX/md/sync_speed_min -- the guaranteed minimum speed + +17. When I create a new array, why does it resynchronise at first? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + See the mdadm(8) manpage: + When creating a RAID5 array, mdadm will automatically create a degraded + array with an extra spare drive. This is because building the spare into + a degraded array is in general faster than resyncing the parity on + a non-degraded, but not clean, array. This feature can be over-ridden with + the --force option. + + This also applies to RAID levels 4 and 6. + + It does not make much sense for RAID levels 1 and 10 and can thus be + overridden with the --force and --assume-clean options, but it is not + recommended. Read the manpage. + +18. How many failed devics can a RAID10 handle? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + (see also question 4b) + + The following table shows how many devices you can lose and still have an + operational array. In some cases, you *can* lose more than the given number + of devices, but there is no guarantee that the array survives. Thus, the + following is the guaranteed number of failed devices a RAID10 array survives + and the maximum number of failed devices the array can (but is not guaranteed + to) handle, given the number of devices used and the number of data block + copies. Note that 2 copies means original + 1 copy. Thus, if you only have + one copy (the original), you cannot handle any failures. + + 1 2 3 4 (# of copies) + 1 0/0 0/0 0/0 0/0 + 2 0/0 1/1 1/1 1/1 + 3 0/0 1/1 2/2 2/2 + 4 0/0 1/2 2/2 3/3 + 5 0/0 1/2 2/2 3/3 + 6 0/0 1/3 2/3 3/3 + 7 0/0 1/3 2/3 3/3 + 8 0/0 1/4 2/3 3/4 + (# of devices) + + Note: I have not really verified the above information. Please don't count + on it. If a device fails, replace it as soon as possible. Corrections welcome. + +19. What should I do if a device fails? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + Replace it as soon as possible. + + In case of physical devices with no hot-swap capabilities, for example via: + + mdadm --remove /dev/md0 /dev/sda1 + poweroff + <replace device and start the machine> + mdadm --add /dev/md0 /dev/sda1 + +20. So how do I find out which other device(s) can fail without killing the + array? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + Did you read the previous question and its answer? + + For cases when you have two copies of each block, the question is easily + answered by looking at the output of /proc/mdstat. For instance on a 4 device + array: + + md3 : active raid10 sdg7[3] sde7[0] sdh7[2] sdf7[1] + + you know that sde7/sdf7 form one pair and sdg7/sgh7 the other. + + If sdh now fails, this will become + + md3 : active raid10 sdg7[3] sde7[0] sdh7[4](F) sdf7[1] + + So now the second pair is degraded; the array could take another failure in + the first pair, but if sdg now also fails, you're history. + + Now go and read question 19. + + For cases with more copies per block, it becomes more complicated. Let's + think of a 7 device array with three copies: + + md5 : active raid10 sdg7[6] sde7[4] sdb7[5] sdf7[2] sda7[3] sdc7[1] sdd7[0] + + Each mirror now has 7/3 = 2.33 devices to it, so in order to determine groups, + you need to round up. Note how the devices are arranged in decreasing order of + their indices (the number in brackes in /proc/mdstat): + + device: -sdd7- -sdc7- -sdf7- -sda7- -sde7- -sdb7- -sdg7- + group: [ one ][ two ][ three ] + + Basically this means that after two devices failed, you need to make sure that + the third failed device doesn't destroy all copies of any given block. And + that's not always easy as it depends on the layout chosen: whether the + blocks are near (same offset within each group), far (spread apart in a way + to maximise the mean distance), or offset (offset by size/n within each + block). + + I'll leave it up to you to figure things out. Now go read question 19. + +21. Why does the kernel speak of 'resync' when using checkarray? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + Please see README.checkarray and http://thread.gmane.org/gmane.linux.raid/11864 . + + In short: it's a bug. checkarray is actually not a resync, but the kernel + does not distinguish between them. + +22. Can I prioritise the sync process and sync certain arrays before others? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + Upon start, md will resynchronise any unclean arrays, starting in somewhat + random order. Sometimes it's desirable to sync e.g. /dev/md3 first (because + it's the most important), but while /dev/md1 is synchronising, /dev/md3 will + be DELAYED (see /proc/mdstat; only if they share the same physical + components. + + It is possible to delay the synchronisation via /sys: + + echo idle >/sys/block/md1/md/sync_action + + This will cause md1 to go idle and MD to synchronise md3 (or whatever is + queued next; repeat the above for other devices if necessary). MD will also + realise that md1 is still not in sync and queue it for resynchronisation, + so it will sync automatically when its turn has come. + +23. mdadm's init script fails because it cannot find any arrays. What gives? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + This does not happen anymore, if no arrays present in config file, no arrays + will be started. + +24. What happened to mdrun? How do I replace it? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + mdrun used to be the sledgehammer approach to assembling arrays. It has + accumulated several problems over the years (e.g. Debian bug #354705) and + thus has been deprecated and removed with the 2.6.7-2 version of this package. + + If you are still using mdrun, please ensure that you have a valid + /etc/mdadm/mdadm.conf file (run /usr/share/mdadm/mkconf --generate to get + one), and run + + mdadm --assemble --scan --auto=yes + + instead of mdrun. + +25. Why are my arrays marked auto-read-only in /proc/mdstat? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + Arrays are kept read-only until the first write occurs. This allows md to + skip lengthy resynchronisation for arrays that have not been properly shut + down, but which also not have changed. + +26. Why doesn't mdadm find arrays specified in the config file and causes the + boot to fail? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + My boot process dies at an early stage and drops me into the busybox shell. + The last relevant output seems to be from mdadm and is something like + + "/dev/md2 does not exist" + + or + + "No devices listed in conf file found" + + Why does mdadm break my system? + + Short answer: It doesn't, the underlying devices aren't yet available yet + when mdadm runs during the early boot process. + + Long answer: It doesn't, but the drivers of those devices incorrectly + communicate to the kernel that the devices are ready, when in fact they are + not. I consider this a bug in those drivers. Please consider reporting it. + + Workaround: there is nothing mdadm can or will do against this. Fortunately + though, initramfs provides a method, documented at + http://wiki.debian.org/InitramfsDebug. Please append rootdelay=10 (which sets + a delay of 10 seconds before trying to mount the root filesystem) to the + kernel command line and try if the boot now works. + + -- martin f. krafft <madduck@debian.org> Wed, 13 May 2009 09:59:53 +0200 diff --git a/debian/local/doc/README.checkarray b/debian/local/doc/README.checkarray new file mode 100644 index 0000000..8071a4d --- /dev/null +++ b/debian/local/doc/README.checkarray @@ -0,0 +1,33 @@ +checkarray notes +================ + +checkarray will run parity checks across all your redundant arrays. By +default, it is configured to run on the first Sunday of each month, at 01:06 +in the morning. This is realised by asking cron to wake up every Sunday with +/etc/cron.d/mdadm, but then only running the script when the day of the month +is less than or equal to 7. See #380425. + +Cron will try to run the check at "idle I/O priority" (see ionice(1)), so that +the check does not overload the system too much. Note that this will only +work if all the component devices of the array employ the (default) "cfq" I/O +scheduler. See the kernel documentation[0] for information on how to verify +and modify the scheduler. checkarray does not verify this for you. + + 0. http://www.kernel.org/doc/Documentation/block/switching-sched.txt + +If you manually invoke checkarray, it runs with default I/O priority. Should +you need to run a check at a higher (or lower) I/O priority, then have a look +at the --idle, --slow, --fast, and --realtime options. + +'check' is a read-only operation, even though the kernel logs may suggest +otherwise (e.g. /proc/mdstat and several kernel messages will mention +"resync"). Please also see question 21 of the FAQ. + +If, however, while reading, a read error occurs, the check will trigger the +normal response to read errors which is to generate the 'correct' data and try +to write that out - so it is possible that a 'check' will trigger a write. +However in the absence of read errors it is read-only. + +You can cancel a running array check with the -x option to checkarray. + + -- martin f. krafft <madduck@debian.org> Thu, 02 Sep 2010 10:27:29 +0200 diff --git a/debian/local/doc/README.recipes b/debian/local/doc/README.recipes new file mode 100644 index 0000000..3906629 --- /dev/null +++ b/debian/local/doc/README.recipes @@ -0,0 +1,168 @@ +mdadm recipes +============= + +The following examples/recipes may help you with your mdadm experience. I'll +leave it as an exercise to use the correct device names and parameters in each +case. You can find pointers to additional documentation in the README.Debian +file. + +Enjoy. Submissions welcome. + +The latest version of this document is available here: + http://git.debian.org/?p=pkg-mdadm/mdadm.git;a=blob;f=debian/README.recipes;hb=HEAD + +The short options used here are: + + -l Set RAID level. + -n Number of active devices in the array. + -x Specify the number of spare (eXtra) devices in the initial array. + +0. create a new array +~~~~~~~~~~~~~~~~~~~~~ + mdadm --create -l1 -n2 -x1 /dev/md0 /dev/sd[abc]1 # RAID 1, 1 spare + mdadm --create -l5 -n3 -x1 /dev/md0 /dev/sd[abcd]1 # RAID 5, 1 spare + mdadm --create -l6 -n4 -x1 /dev/md0 /dev/sd[abcde]1 # RAID 6, 1 spare + +1. create a degraded array +~~~~~~~~~~~~~~~~~~~~~~~~~~ + mdadm --create -l5 -n3 /dev/md0 /dev/sda1 missing /dev/sdb1 + mdadm --create -l6 -n4 /dev/md0 /dev/sda1 missing /dev/sdb1 missing + +2. assemble an existing array +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + mdadm --assemble --auto=yes /dev/md0 /dev/sd[abc]1 + + # if the array is degraded, it won't be started. use --run: + mdadm --assemble --auto=yes --run /dev/md0 /dev/sd[ab]1 + + # or start it by hand: + mdadm --run /dev/md0 + +3. assemble all arrays in /etc/mdadm/mdadm.conf +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + mdadm --assemble --auto=yes --scan + +4. assemble a dirty degraded array +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + mdadm --assemble --auto=yes --force /dev/md0 /dev/sd[ab]1 + mdadm --run /dev/md0 + +4b. assemble a dirty degraded array at boot-time +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + If the array is started at boot time by the kernel (partition type 0xfd), + you can force-assemble it by passing the kernel boot parameter + + md-mod.start_dirty_degraded=1 + +5. stop arrays +~~~~~~~~~~~~~~ + mdadm --stop /dev/md0 + + # to stop all arrays in /etc/mdadm/mdadm.conf + mdadm --stop --scan + +6. hot-add components +~~~~~~~~~~~~~~~~~~~~~ + # on the running array: + mdadm --add /dev/md0 /dev/sdc1 + + # if you add more components than the array was setup with, additional + # components will be spares + +7. hot-remove components +~~~~~~~~~~~~~~~~~~~~~~~~ + # on the running array: + mdadm --fail /dev/md0 /dev/sdb1 + + # if you have configured spares, watch /proc/mdstat how it fills in + mdadm --remove /dev/md0 /dev/sdb1 + +8. hot-grow a RAID1 by adding new components +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + # on the running array, in either order: + mdadm --grow -n3 /dev/md0 + mdadm --add /dev/md0 /dev/sdc1 + + # note: without growing first, additional devices become spares and are + # *not* synchronised after the add. + +9. hot-shrink a RAID1 by removing components +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + mdadm --fail /dev/md0 /dev/sdc1 + mdadm --remove /dev/md0 /dev/sdc1 + mdadm --grow -n2 /dev/md0 + +10. convert existing filesystem to RAID 1 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + # The idea is to create a degraded RAID 1 on the second partition, move + # data, then hot add the first. This seems safer to me than simply to + # force-add a superblock to the existing filesystem. + # + # Assume /dev/sda1 holds the data (and let's assume it's mounted on + # /home) and /dev/sdb1 is empty and of the same size... + # + mdadm --create /dev/md0 -l1 -n2 /dev/sdb1 missing + + mkfs -t <type> /dev/md0 + mount /dev/md0 /mnt + + tar -cf- -C /home . | tar -xf- -C /mnt -p + + # consider verifying the data + umount /home + umount /mnt + mount /dev/md0 /home # also change /etc/fstab + + mdadm --add /dev/md0 /dev/sda1 + + Warren Togami has a document explaining how to convert a filesystem on + a remote system via SSH: http://togami.com/~warren/guides/remoteraidcrazies/ + +10b. convert existing filesystem to RAID 1 in-place +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + In-place conversion of /dev/sda1 to /dev/md0 is effectively + + mdadm --create /dev/md0 -l1 -n2 /dev/sda1 missing + + however, do NOT do this, as you risk filesystem corruption. + + If you need to do this, first unmount and shrink the filesystem by + a megabyte (if supported). Then run the above command, then (optionally) + again grow the filesystem as much as possible. + + Do make sure you have backups. If you do not yet, consider method (10) + instead (and make backups anyway!). + +11. convert existing filesystem to RAID 5/6 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + # See (10) for the basics. + mdadm --create /dev/md0 -l5 -n3 /dev/sdb1 /dev/sdc1 missing + + #mdadm --create /dev/md0 -l6 -n4 /dev/sdb1 /dev/sdc1 /dev/sdd1 missing + mkfs -t <type> /dev/md0 + mount /dev/md0 /mnt + + tar -cf- -C /home . | tar -xf- -C /mnt -p + + # consider verifying the data + umount /home + umount /mnt + mount /dev/md0 /home # also change /etc/fstab + + mdadm --add /dev/md0 /dev/sda1 + +12. change the preferred minor of an MD array (RAID) +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + # you need to manually assemble the array to change the preferred minor + # if you manually assemble, the superblock will be updated to reflect + # the preferred minor as you indicate with the assembly. + # for example, to set the preferred minor to 4: + mdadm --assemble /dev/md4 /dev/sd[abc]1 + + # this only works on 2.6 kernels, and only for RAID levels of 1 and above. + # for other MD arrays, you need to specify --update explicitly: + mdadm --assemble --update=super-minor /dev/md4 /dev/sd[abc]1 + + # see also item 12 in the FAQ contained with the Debian package. + + -- martin f. krafft <madduck@debian.org> Fri, 06 Oct 2006 15:39:58 +0200 diff --git a/debian/local/initramfs-tools/local-block/mdadm b/debian/local/initramfs-tools/local-block/mdadm new file mode 100755 index 0000000..214f24c --- /dev/null +++ b/debian/local/initramfs-tools/local-block/mdadm @@ -0,0 +1,61 @@ +#!/bin/sh + +PREREQ="multipath" + +prereqs() +{ + echo "$PREREQ" +} + +case $1 in +# get pre-requisites +prereqs) + prereqs + exit 0 + ;; +esac + +. /scripts/functions + +# Poor man's mdadm-last-resort@.timer +# That kicks in 2/3rds into the ROOTDELAY + +if [ ! -f /run/count.mdadm.initrd ] +then + COUNT=0 + + # Unfortunately raid personalities can be registered _after_ block + # devices have already been added, and their rules processed, try + # triggering again. See #830770 + udevadm trigger --action=add -s block || true + wait_for_udev 10 +else + COUNT=$(cat /run/count.mdadm.initrd) +fi +COUNT=$((COUNT + 1)) + +echo $COUNT > /run/count.mdadm.initrd + +# Run pure assemble command, even though we default to incremental +# assembly it is supported for users to export variables via +# param.conf such as IMSM_NO_PLATFORM. See #830300 +mdadm -q --assemble --scan --no-degraded || true + +MAX=30 +if [ ${ROOTDELAY:-0} -gt $MAX ]; then + MAX=$ROOTDELAY +fi +MAX=$((MAX*2/3)) + +if [ "$COUNT" = "$MAX" ] +then + # Poor man's mdadm-last-resort@.service for incremental devices + mdadm -q --run /dev/md?* + + # And last try for all others + mdadm -q --assemble --scan --run + + rm -f /run/count.mdadm.initrd +fi + +exit 0 diff --git a/debian/local/initramfs-tools/local-bottom/mdadm b/debian/local/initramfs-tools/local-bottom/mdadm new file mode 100755 index 0000000..eda3b17 --- /dev/null +++ b/debian/local/initramfs-tools/local-bottom/mdadm @@ -0,0 +1,3 @@ +#!/bin/sh +rm -f /run/count.mdadm.initrd +exit 0
\ No newline at end of file diff --git a/debian/local/reportbug/script b/debian/local/reportbug/script new file mode 100755 index 0000000..dcb88eb --- /dev/null +++ b/debian/local/reportbug/script @@ -0,0 +1,219 @@ +#!/bin/bash +# +# mdadm bug submission control script +# +# allows Debian's bug tools to include relevant information in bug reports. +# +# Copyright © martin f. krafft <madduck@debian.org> +# distributed under the terms of the Artistic Licence 2.0 +# +# we need /bin/bash for readline and -n capabalities in the prompt(s) +# + +# maximise information output even in the case of errors +set +eu + +if ! command -v yesno >/dev/null; then + if [ -r /usr/share/reportbug/handle_bugscript ]; then + exec /usr/share/reportbug/handle_bugscript ". $0" /dev/stdout + fi + yesno() { + read -n1 -p"$1" REPLY + case "$REPLY" in + [yY]) REPLY=yep;; + [nN]) REPLY=nop;; + ('') REPLY="$2";; + esac + } + exec 3>&1 +fi + +# do not let people ctrl-c out of the bugscript +trap : INT + +if [ $(id -u) != 0 ]; then + if [ -x "$(command -v sudo)" ]; then + yesno "Gather system information as root using sudo? (Y/n) " yep + if [ "$REPLY" = yep ]; then + echo running sudo "$0" "$@"... + sudo "$0" "$@" >&3 && exit 0 + echo "sudo invocation failed, trying /bin/su..." + fi + fi + + yesno "Gather system information as root using su? (Y/n) " yep + if [ "$REPLY" = yep ]; then + ARGS= + for i in "$@"; do ARGS="${ARGS:+$ARGS }'$1'"; shift; done + echo "running su root -s '/bin/sh -c $0${ARGS:+ $ARGS}'..." + su root -s /bin/sh -c "$0 $ARGS" >&3 && exit 0 + unset ARGS + echo "su invocation failed." + fi + + # arrive here only if neither sudo nor su worked: + yesno "Will you provide system information in the bug report yourself? (N/y) " nop + if [ "$REPLY" = yep ]; then + cat <<_eof >&3 + +IMPORTANT: + please do not forget to include all relevant system information with this + bug report. You could run + /usr/share/bug/mdadm/script 3>&1 + as root and attach or include the output. + +_eof + exit 0 + fi + + # try our best + cat <<_eof >&3 + +WARNING: + the following output was not generated by the root user. If you can, please + replace the following up until "-- System Information:" with the output of + /usr/share/bug/mdadm/script 3>&1 + run as root. Thanks! + +_eof +fi + +if [ ! -r /proc/mdstat ]; then + echo "The local system does not have MD (RAID) support: no drivers loaded." + echo "Without MD support, I cannot collect as much information as I'd like." + + #yesno "Are you sure you want to report a bug at this time? " yep + yesno "Hit any key to continue..." yep + #[ "$REPLY" = yep ] || exit 1 +fi + +echo "--- mdadm.conf" >&3 +if [ -r /etc/mdadm/mdadm.conf ]; then + grep '^[^#]' /etc/mdadm/mdadm.conf >&3 +elif [ -r /etc/mdadm.conf ]; then + grep '^[^#]' /etc/mdadm.conf >&3 +else + echo no mdadm.conf file. >&3 +fi +echo >&3 + +echo "--- /etc/default/mdadm" >&3 +if [ -r /etc/default/mdadm ]; then + grep '^[^#]' /etc/default/mdadm >&3 +else + echo no /etc/default/mdadm file. >&3 +fi +echo >&3 + +echo "--- /proc/mdstat:" >&3 +cat /proc/mdstat >&3 2>&3 || : +echo >&3 + +echo "--- /proc/partitions:" >&3 +cat /proc/partitions >&3 2>&3 || : +echo >&3 + +echo "--- LVM physical volumes:" >&3 +if [ -x "$(command -v pvs)" ]; then + pvs >&3 +else + echo "LVM does not seem to be used." >&3 +fi + +echo "--- mount output" >&3 +mount >&3 +echo >&3 + +echo "--- initrd.img-$(uname -r):" >&3 +if [ -r /boot/initrd.img-$(uname -r) ]; then + TEMPDIR=$(mktemp -d) + OLDPWD="$PWD" + cd "$TEMPDIR" + zcat /boot/initrd.img-$(uname -r) 2>&3 | cpio -i 2>&3 + find -regex '.*/md[a/].+' -type f -exec md5sum {} \; >&3 + + echo >&3 + echo "--- initrd's /conf/conf.d/md:" >&3 + if [ -r conf/conf.d/md ]; then + cat conf/conf.d/md >&3 + else + echo "no conf/md file." >&3 + fi + + cd "$OLDPWD" + rm -rf "$TEMPDIR" + unset TEMPDIR +else + echo "no initrd.img-$(uname -r) found." >&3 +fi +echo >&3 + +if [ -r /proc/modules ]; then + echo "--- /proc/modules:" >&3 + egrep '(dm_|raid|linear|multipath|faulty)' < /proc/modules >&3 || : + echo >&3 +fi + +if [ -f /var/log/syslog ]; then + if [ -r /var/log/syslog ]; then + echo "--- /var/log/syslog:" >&3 + egrep "^\w{3} [ :[:digit:]]{11} ($(hostname)|localhost) (kernel: md|mdadm): " /var/log/syslog >&3 || : + echo >&3 + else + echo "syslog not readable by user." >&3 + fi +fi + +echo "--- volume detail:" >&3 +for dev in /dev/[hsv]d[a-z]*; do + [ ! -r $dev ] && echo "$dev not readable by user." && continue + mdadm -E $dev 2>/dev/null && echo -- || echo "$dev is not recognised by mdadm." +done >&3 +echo >&3 + +if [ -r /proc/cmdline ]; then + echo "--- /proc/cmdline" >&3 + cat /proc/cmdline >&3 + echo >&3 +fi + +if [ -f /boot/grub/grub.cfg ]; then + echo "--- grub2:" >&3 + if [ -r /boot/grub/grub.cfg ]; then + egrep '^[^#].*\<(root=|raid)' /boot/grub/grub.cfg >&3 || : + else + echo grub.cfg file not readable. >&3 + fi + echo >&3 +fi + +if [ -f /boot/grub/menu.lst ]; then + echo "--- grub legacy:" >&3 + if [ -r /boot/grub/menu.lst ]; then + grep '^[^#].*\<root=' /boot/grub/menu.lst >&3 || : + else + echo menu.lst file not readable. >&3 + fi + echo >&3 +fi + +if [ -f /etc/lilo.conf ]; then + echo "--- lilo:" >&3 + if [ -r /etc/lilo.conf ]; then + egrep '^([^#].*)?root=' /etc/lilo.conf >&3 || : + else + echo lilo.conf file not readable. >&3 + fi + echo >&3 +fi + +echo "--- udev:" >&3 +COLUMNS=70 dpkg -l udev | grep '\<udev\>' >&3 +md5sum /etc/udev/rules.d/*md* /lib/udev/rules.d/*md* >&3 2>/dev/null +echo >&3 + +echo "--- /dev:" >&3 +ls -l /dev/md* /dev/disk/by-* >&3 +echo >&3 + +echo "Auto-generated on $(date -R) by mdadm bugscript" >&3 |