From cfe5e3905201349e9cf3f95d52ff4bd100bde37d Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 14 Apr 2024 21:10:49 +0200 Subject: Adding upstream version 2.39.3. Signed-off-by: Daniel Baumann --- disk-utils/mkswap.8.adoc | 125 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 disk-utils/mkswap.8.adoc (limited to 'disk-utils/mkswap.8.adoc') diff --git a/disk-utils/mkswap.8.adoc b/disk-utils/mkswap.8.adoc new file mode 100644 index 0000000..904467d --- /dev/null +++ b/disk-utils/mkswap.8.adoc @@ -0,0 +1,125 @@ +//po4a: entry man manual +//// +Copyright 1998 Andries E. Brouwer (aeb@cwi.nl) +May be distributed under the GNU General Public License +//// += mkswap(8) +:doctype: manpage +:man manual: System Administration +:man source: util-linux {release-version} +:page-layout: base +:command: mkswap + +== NAME + +mkswap - set up a Linux swap area + +== SYNOPSIS + +*mkswap* [options] _device_ [_size_] + +== DESCRIPTION + +*mkswap* sets up a Linux swap area on a device or in a file. + +The _device_ argument will usually be a disk partition (something like _/dev/sdb7_) but can also be a file. The Linux kernel does not look at partition IDs, but many installation scripts will assume that partitions of hex type 82 (LINUX_SWAP) are meant to be swap partitions. (*Warning: Solaris also uses this type. Be careful not to kill your Solaris partitions.*) + +The _size_ parameter is superfluous but retained for backwards compatibility. (It specifies the desired size of the swap area in 1024-byte blocks. *mkswap* will use the entire partition or file if it is omitted. Specifying it is unwise - a typo may destroy your disk.) + +After creating the swap area, you need the *swapon*(8) command to start using it. Usually swap areas are listed in _/etc/fstab_ so that they can be taken into use at boot time by a *swapon -a* command in some boot script. + +== WARNING + +The swap header does not touch the first block. A boot loader or disk label can be there, but it is not a recommended setup. The recommended setup is to use a separate partition for a Linux swap area. + +*mkswap*, like many others mkfs-like utils, *erases the first partition block to make any previous filesystem invisible.* + +However, *mkswap* refuses to erase the first block on a device with a disk label (SUN, BSD, ...). + +== OPTIONS + +*-c*, *--check*:: +Check the device (if it is a block device) for bad blocks before creating the swap area. If any bad blocks are found, the count is printed. + +*-f*, *--force*:: +Go ahead even if the command is stupid. This allows the creation of a swap area larger than the file or partition it resides on. ++ +Also, without this option, *mkswap* will refuse to erase the first block on a device with a partition table. + +*-q*, *--quiet*:: +Suppress output and warning messages. + +*-L*, *--label* _label_:: +Specify a _label_ for the device, to allow *swapon*(8) by label. + +*--lock*[=_mode_]:: +Use exclusive BSD lock for device or file it operates. The optional argument _mode_ can be *yes*, *no* (or 1 and 0) or *nonblock*. If the _mode_ argument is omitted, it defaults to *yes*. This option overwrites environment variable *$LOCK_BLOCK_DEVICE*. The default is not to use any lock at all, but it's recommended to avoid collisions with *systemd-udevd*(8) or other tools. + +*-p*, *--pagesize* _size_:: +Specify the page _size_ (in bytes) to use. This option is usually unnecessary; *mkswap* reads the size from the kernel. + +*-U*, *--uuid* _UUID_:: +Specify the _UUID_ to use. The default is to generate a UUID. The format of the UUID is a series of +hex digits separated by hyphens, like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16". The UUID parameter +may also be one of the following: ++ +*clear*;; +clear the filesystem UUID +*random*;; +generate a new randomly-generated UUID +*time*;; +generate a new time-based UUID + +*-e*, *--endianness* _ENDIANNESS_:: +Specify the _ENDIANNESS_ to use, valid arguments are *native*, *little* or *big*. The default is *native*. + +*-v*, *--swapversion 1*:: +Specify the swap-space version. (This option is currently pointless, as the old *-v 0* option has become obsolete and now only *-v 1* is supported. The kernel has not supported v0 swap-space format since 2.5.22 (June 2002). The new version v1 is supported since 2.1.117 (August 1998).) + +*--verbose*:: +Verbose execution. With this option *mkswap* will output more details about detected problems during swap area set up. + +include::man-common/help-version.adoc[] + +== ENVIRONMENT + +LIBBLKID_DEBUG=all:: +enables libblkid debug output. + +LOCK_BLOCK_DEVICE=:: +use exclusive BSD lock. The mode is "1" or "0". See *--lock* for more details. + +== NOTES + +The maximum useful size of a swap area depends on the architecture and the kernel version. + +The maximum number of the pages that is possible to address by swap area header is 4294967295 (32-bit unsigned int). The remaining space on the swap device is ignored. + +Presently, Linux allows 32 swap areas. The areas in use can be seen in the file _/proc/swaps_. + +*mkswap* refuses areas smaller than 10 pages. + +If you don't know the page size that your machine uses, you can look it up with *getconf PAGESIZE*. + +To set up a swap file, it is necessary to create that file before initializing it with *mkswap*, e.g. using a command like + +.... +# dd if=/dev/zero of=swapfile bs=1MiB count=$((8*1024)) +.... + +to create 8GiB swapfile. + +Please read notes from *swapon*(8) about *the swap file use restrictions* (holes, preallocation and copy-on-write issues). + +== SEE ALSO + +*fdisk*(8), +*swapon*(8) + +include::man-common/bugreports.adoc[] + +include::man-common/footer.adoc[] + +ifdef::translation[] +include::man-common/translation.adoc[] +endif::[] -- cgit v1.2.3