1SWAPON(8) Linux Programmer's Manual SWAPON(8)
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6 swapon, swapoff - enable/disable devices and files for paging and swap‐
7 ping
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10 Get info:
11 swapon -s [-h] [-V]
12
13 Enable/disable:
14 swapon [-f] [-p priority] [-v] specialfile...
15 swapoff [-v] specialfile...
16
17 Enable/disable all:
18 swapon -a [-e] [-f] [-v]
19 swapoff -a [-v]
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22 swapon is used to specify devices on which paging and swapping are to
23 take place.
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25 The device or file used is given by the specialfile parameter. It may
26 be of the form -L label or -U uuid to indicate a device by label or
27 uuid.
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29 Calls to swapon normally occur in the system boot scripts making all
30 swap devices available, so that the paging and swapping activity is
31 interleaved across several devices and files.
32
33 swapoff disables swapping on the specified devices and files. When the
34 -a flag is given, swapping is disabled on all known swap devices and
35 files (as found in /proc/swaps or /etc/fstab).
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37
38 -a, --all
39 All devices marked as ``swap'' in /etc/fstab are made available,
40 except for those with the ``noauto'' option. Devices that are
41 already being used as swap are silently skipped.
42
43 -e, --ifexists
44 Silently skip devices that do not exist.
45
46 -f, --fixpgsz
47 Reinitialize (exec /sbin/mkswap) the swap space if its page size
48 does not match that of the the current running kernel.
49 mkswap(2) initializes the whole device and does not check for
50 bad blocks.
51
52 -h, --help
53 Provide help.
54
55 -L label
56 Use the partition that has the specified label. (For this,
57 access to /proc/partitions is needed.)
58
59 -p, --priority priority
60 Specify the priority of the swap device. priority is a value
61 between 0 and 32767. Higher numbers indicate higher priority.
62 See swapon(2) for a full description of swap priorities. Add
63 pri=value to the option field of /etc/fstab for use with swapon
64 -a.
65
66 -s, --summary
67 Display swap usage summary by device. Equivalent to "cat
68 /proc/swaps". Not available before Linux 2.1.25.
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70 -U uuid
71 Use the partition that has the specified uuid.
72
73 -v, --verbose
74 Be verbose.
75
76 -V, --version
77 Display version.
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80 You should not use swapon on a file with holes. Swap over NFS may not
81 work.
82
83 swapon automatically detects and rewrites swap space signature with old
84 software suspend data (e.g S1SUSPEND, S2SUSPEND, ...). The problem is
85 that if we don't do it, then we get data corruption the next time an
86 attempt at unsuspending is made.
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89 swapon(2), swapoff(2), fstab(5), init(8), mkswap(8), rc(8), mount(8)
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92 /dev/sd?? standard paging devices
93 /etc/fstab ascii filesystem description table
94
96 The swapon command appeared in 4.0BSD.
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99 The swapon command is part of the util-linux-ng package and is avail‐
100 able from ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
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104Linux 1.x 25 September 1995 SWAPON(8)