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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-06-03 14:01:35 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-06-03 14:01:35 +0000 |
commit | e6f2eaf47a177a8eca054d1d70a1b6287e8c3521 (patch) | |
tree | c5719e819a9e37df4b54affd61438f382ec38a8f /man/dracut.cmdline.7.asc | |
parent | Adding upstream version 060+5. (diff) | |
download | dracut-e6f2eaf47a177a8eca054d1d70a1b6287e8c3521.tar.xz dracut-e6f2eaf47a177a8eca054d1d70a1b6287e8c3521.zip |
Adding upstream version 102.upstream/102
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'man/dracut.cmdline.7.asc')
-rw-r--r-- | man/dracut.cmdline.7.asc | 230 |
1 files changed, 148 insertions, 82 deletions
diff --git a/man/dracut.cmdline.7.asc b/man/dracut.cmdline.7.asc index fefa209..7c0051e 100644 --- a/man/dracut.cmdline.7.asc +++ b/man/dracut.cmdline.7.asc @@ -221,13 +221,11 @@ It should be attached to any report about dracut problems. drop to a shell at the end **rd.break=**__{cmdline|pre-udev|pre-trigger|initqueue|pre-mount|mount|pre-pivot|cleanup}__:: - drop to a shell before the defined breakpoint starts - -**rd.udev.info**:: - set udev to loglevel info + drop to a shell before the defined breakpoint starts. + This parameter can be specified multiple times. -**rd.udev.debug**:: - set udev to loglevel debug +**rd.udev.log_level=**__{err|info|debug}__:: + set udev log level. The default is 'err'. I18N ~~~~ @@ -972,19 +970,38 @@ root=virtiofs:host rw DASD ~~~~ **rd.dasd=**....:: - same syntax as the kernel module parameter (s390 only) + same syntax as the kernel module parameter (s390 only). + For more details on the syntax see the IBM book + "Linux on IBM Z and IBM LinuxONE - Device Drivers, Features, and Commands" + https://www.ibm.com/docs/en/linux-on-systems?topic=overview-device-drivers-features-commands. + This parameter can be specified multiple times. ++ +NOTE: + This parameter is no longer handled by dracut itself but with the exact + same syntax by + https://github.com/ibm-s390-linux/s390-tools/tree/master/zdev/dracut/95zdev. ZFCP ~~~~ **rd.zfcp=**__<zfcp adaptor device bus ID>__,__<WWPN>__,__<FCPLUN>__:: rd.zfcp can be specified multiple times on the kernel command line. ++ +NOTE: + This parameter is no longer handled by dracut itself but with the exact + same syntax by + https://github.com/ibm-s390-linux/s390-tools/tree/master/zdev/dracut/95zdev. **rd.zfcp=**__<zfcp adaptor device bus ID>__:: If NPIV is enabled and the 'allow_lun_scan' parameter to the zfcp - module is set to 'Y' then the zfcp adaptor will be initiating a + module is set to 'Y' then the zfcp driver will be initiating a scan internally and the <WWPN> and <FCPLUN> parameters can be omitted. + +NOTE: + This parameter is no longer handled by dracut itself but with the exact + same syntax by + https://github.com/ibm-s390-linux/s390-tools/tree/master/zdev/dracut/95zdev. ++ [listing] .Example -- @@ -998,9 +1015,12 @@ rd.zfcp=0.0.4000 ZNET ~~~~ **rd.znet=**__<nettype>__,__<subchannels>__,__<options>__:: - The whole parameter is appended to /etc/ccw.conf, which is used on - RHEL/Fedora with ccw_init, which is called from udev for certain - devices on z-series. + Activates a channel-attached network interface on s390 architecture. + <nettype> is one of: qeth, lcs, ctc. + <subchannels> is a comma-separated list of ccw device bus-IDs. + The list consists of 3 entries with nettype qeth, and 2 for other nettype. + <options> is a comma-separated list of <name>=<value> pairs, + where <name> refers to a device sysfs attribute to which <value> gets written. rd.znet can be specified multiple times on the kernel command line. **rd.znet_ifname=**__<ifname>__:__<subchannels>__:: @@ -1020,51 +1040,88 @@ Booting live images Dracut offers multiple options for live booted images: ===================== -SquashFS with read-only filesystem image::: The system will boot with a -read-only filesystem from the SquashFS and apply a writable Device-mapper -snapshot or an OverlayFS overlay mount for the read-only base filesystem. This -method ensures a relatively fast boot and lower RAM usage. Users **must be -careful** to avoid writing too many blocks to a snapshot volume. Once the -blocks of the snapshot overlay are exhausted, the root filesystem becomes -read-only and may cause application failures. The snapshot overlay file is -marked 'Overflow', and a difficult recovery is required to repair and enlarge -the overlay offline. Non-persistent overlays are sparse files in RAM that only -consume content space as required blocks are allocated. They default to an -apparent size of 32 GiB in RAM. The size can be adjusted with the -**rd.live.overlay.size=** kernel command line option. -+ -The filesystem structure is traditionally expected to be: -+ +SquashFS (read-only) base filesystem image::: +Note -- There are 3 separate overlay types available: +- Device-mapper snapshots (the original offering), +- Device-mapper thin provisioning snapshots (see *_rd.live.overlay.thin_*, +a later offering), and +- OverlayFS based overlay mounts (a more recent offering). + ++ +-- +Using one of these technologies, the system will provide a writable overlay for +the base, read-only SquashFS root filesystem. These methods enable a relatively +fast boot and lower RAM usage. + +With the original Device-mapper snapshot overlay, users **must be careful** to +avoid writing too many blocks to the snapshot device. Once the blocks of the +snapshot overlay are exhausted, the whole root filesystem becomes read-only +leading to application failures. The snapshot overlay device is marked +'Overflow', and a difficult recovery is required to repair and enlarge the +overlay offline. + +When *_rd.live.overlay=_* is not specified for persistent overlay storage, or +the specified file is not found or writable, a Device-mapper snapshot based +non-persistent or temporary overlay is automatically created as a sparse file +in RAM of the initramfs. This file will only consume content space as required +blocks are allocated. This snapshot based overlay defaults to an apparent size +of 32 GiB in RAM, and can be adjusted with the *_rd.live.overlay.size=_* kernel +command line option. This file is hidden (and appears deleted) when the boot +process switches out of the initramfs to the main root filesystem but its loop +device remains connected to the Device-mapper snapshot. + +Even with large Device-mapper overlay files for write space, the available root +filesystem capacity is limited by the total allocated size of the base root +filesystem, which often provide only a small number of gigabytes of free space. + +This shortage could be remedied by building the root filesystem with more +allocated free space, or the OverlayFS based overlay mount method can be used. + +When the *_rd.live.overlay.overlayfs_* option is specified or when +*_rd.live.overlay=_* points to an appropriate directory with a sister at +`/../ovlwork`, then an OverlayFS based overlay mount is employed. Such a +persistent OverlayFS overlay can extend the available root filesystem storage +up to the capacity of the LiveOS disk device. + +For non-persistent OverlayFS overlays, the `/run/overlayfs` directory in the +`/run` tmpfs is used for temporary storage. This filesystem is typically sized +to one half of the RAM total in the system. + +The command: `mount -o remount,size=<nbytes> /run` will resize this virtual +filesystem after booting. + +The internal SquashFS structure is traditionally expected to be: + [listing] --- +---- squashfs.img | SquashFS from LiveCD .iso !(mount) /LiveOS - |- rootfs.img | Filesystem image to mount read-only + |- rootfs.img | Usually a ext4 filesystem image to mount read-only !(mount) - /bin | Live filesystem + /bin | Base Live root filesystem /boot | /dev | ... | --- -+ -For OverlayFS mount overlays, the filesystem structure may also be a direct +---- + +For OverlayFS mount overlays, the internal SquashFS structure may be a direct compression of the root filesystem: -+ + [listing] --- +---- squashfs.img | SquashFS from LiveCD .iso !(mount) - /bin | Live filesystem + /bin | Base Live root filesystem /boot | /dev | ... | --- -+ +---- + Dracut uses one of the overlay methods of live booting by default. No -additional command line options are required other than **root=live:<URL>** to -specify the location of your squashed filesystem. -+ +additional command line options are required other than +**root=**live:__<path to blockdevice>__ or **root=**live:__<URL>__ to specify +the location of your squashed root filesystem. + - The compressed SquashFS image can be copied during boot to RAM at `/run/initramfs/squashed.img` by using the **rd.live.ram=1** option. - A device with a persistent overlay can be booted read-only by using the @@ -1072,7 +1129,8 @@ specify the location of your squashed filesystem. either cause a temporary, writable overlay to be stacked over a read-only snapshot of the root filesystem or the OverlayFS mount will use an additional lower layer with the root filesystem. -+ +-- + Uncompressed live filesystem image::: When the live system was installed with the '--skipcompress' option of the __livecd-iso-to-disk__ installation script for Live USB devices, the root @@ -1161,29 +1219,36 @@ Copy the complete image to RAM and use this for booting. This is useful when the image resides on, e.g., a DVD which needs to be ejected later on. **rd.live.overlay={**__<devspec>__[:__{<pathspec>|auto}__]|__none__}:: -Manage the usage of a permanent overlay. +Manage the usage of a persistent overlay. + -- -* _<devspec>_ specifies the path to a device with a mountable filesystem. -* _<pathspec>_ is the path to a file within that filesystem, which shall be -used to persist the changes made to the device specified by the -**root=live:__<url>__** option. -+ -The default _pathspec_, when _auto_ or no _:<pathspec>_ is given, is -`/<rd.live.dir>/overlay-<label>-<uuid>`, where _<label>_ is the -device LABEL, and _<uuid>_ is the device UUID. -* _none_ (the word itself) specifies that no overlay will be used, such as when -an uncompressed, writable live root filesystem is available. -+ -If a persistent overlay __is detected__ at the standard LiveOS path, the -overlay & overlay type detected, whether Device-mapper or OverlayFS, will be -used. +* *_<devspec>_* specifies the path to a device with a mountable filesystem. +* *_<pathspec>_* is a path within the *_<devspec>_* filesystem to either +** a file (that is loop mounted for a Device-mapper overlay) or +** a directory (that is symbolically linked to `/run/overlayfs` for a OverlayFS +mount overlay). (A required sister directory `/<pathspec>/../ovlwork` is +automatically made.) +* *_none_* (the word itself) specifies that no overlay will be used, such as +when an uncompressed, writable live root filesystem is available. + +The above method shall be used to persist the changes made to the root +filesystem specified within the + +**root=**live:__<path to blockdevice>__ or **root=**live:__<url>__ device. + +The default *_pathspec_*, when *:auto* or +no **:__<pathspec>__** is given, is `/<rd.live.dir>/overlay-<label>-<uuid>`, +where _<label>_ and _<uuid>_ are the LABEL and UUID of the filesystem specified +by the **root=**live:__<path|url>__ device. + +If a persistent overlay __is detected__ at the standard LiveOS path, +and *_rd.live.overlay.overlayfs_* is not set to 1, the overlay type (either +Device-mapper or OverlayFS) will be detected and it will be used. -- + [listing] .Examples -- -rd.live.overlay=/dev/sdb1:persistent-overlay.img +rd.live.overlay=/dev/sdb1:/persistent-overlay.img rd.live.overlay=UUID=99440c1f-8daa-41bf-b965-b7240a8996f4 -- @@ -1196,15 +1261,16 @@ Specifies a non-persistent Device-mapper overlay size in MiB. The default is _32768_. **rd.live.overlay.readonly=**1:: -This is used to boot with a normally read-write persistent overlay in a -read-only mode. With this option, either an additional, non-persistent, -writable snapshot overlay will be stacked over a read-only snapshot, -`/dev/mapper/live‑ro`, of the base filesystem with the persistent overlay, or a -read-only loop device, in the case of a writable __rootfs.img__, or an OverlayFS -mount will use the persistent overlay directory linked at `/run/overlayfs‑r` as -an additional lower layer along with the base root filesystem and apply a -transient, writable upper directory overlay, in order to complete the booted -root filesystem. +This is used to boot in a read-only mode with a normally read-write persistent +overlay. With this option, +* Device-mapper overlays will have an additional, non-persistent, writable +snapshot overlay stacked over a read-only snapshot (`/dev/mapper/live‑ro`) +of the base root filesystem and the persistent overlay, or +* for writable `rootfs.img` images, the above over a read-only loop device, or +* an OverlayFS mount will link the persistent overlay directory at +`/run/overlayfs‑r` as an additional read-only lower layer stacked over the base +root filesystem, and `/run/overlayfs` becomes the temporary, writable, upper +directory overlay, to complete the bootable root filesystem. **rd.live.overlay.reset=**1:: Specifies that a persistent overlay should be reset on boot. All previous root @@ -1222,18 +1288,15 @@ Enables the use of the *OverlayFS* kernel module, if available, to provide a copy-on-write union directory for the root filesystem. OverlayFS overlays are directories of the files that have changed on the read-only base (lower) filesystem. The root filesystem is provided through a special overlay type -mount that merges the lower and upper directories. If an OverlayFS upper -directory is not present on the boot device, a tmpfs directory will be created -at `/run/overlayfs` to provide temporary storage. Persistent storage can be -provided on vfat or msdos formatted devices by supplying the OverlayFS upper -directory within an embedded filesystem that supports the creation of trusted.* -extended attributes and provides a valid d_type in readdir responses, such as -with ext4 and xfs. On non-vfat-formatted devices, a persistent OverlayFS -overlay can extend the available root filesystem storage up to the capacity of -the LiveOS disk device. -+ -If a persistent overlay is detected at the standard LiveOS path, the overlay & -overlay type detected, whether OverlayFS or Device-mapper, will be used. +mount that merges at least two directories, designated the lower and the upper. +If an OverlayFS upper directory is not present on the boot device, a tmpfs +directory will be created at `/run/overlayfs` to provide temporary storage. +Persistent storage can be provided on vfat or msdos formatted devices by +supplying the OverlayFS upper directory within an embedded filesystem that +supports the creation of trusted.* extended attributes and provides a valid +d_type in readdir responses, such as with btrfs, ext4, f2fs, & xfs. On +non-vfat-formatted devices, a persistent OverlayFS overlay can extend the +available root filesystem storage up to the capacity of the LiveOS disk device. + The **rd.live.overlay.readonly** option, which allows a persistent overlayfs to be mounted read-only through a higher level transient overlay directory, has @@ -1326,8 +1389,7 @@ ecryptfskey=/etc/keys/ecryptfs-trusted.blob Deprecated, renamed Options ~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Here is a list of options, which were used in dracut prior to version 008, and -their new replacement. +Here is a list of options and their new replacement. rdbreak:: rd.break @@ -1428,9 +1490,13 @@ rdshell:: rd.shell rd_NO_SPLASH:: rd.splash -rdudevdebug:: rd.udev.debug +rdudevdebug:: rd.udev.udev_log=debug + +rdudevinfo:: rd.udev.udev_log=info + +rd.udev.debug:: rd.udev.udev_log=debug -rdudevinfo:: rd.udev.info +rd.udev.info:: rd.udev.udev_log=info rd_NO_ZFCPCONF:: rd.zfcp.conf=0 |