Usage:
swapon -a [-e] [-v] [-f] enable all swaps from /etc/fstab
swapon [-p priority] [-v] [-f] <special> enable given swap
swapon -s display swap usage summary
swapon -h display help
swapon -V display versionThe <special> parameter:
{-L label | LABEL=label} LABEL of device to be used
{-U uuid | UUID=uuid} UUID of device to be used
<device> name of device to be used
<file> name of file to be used
swapoff
Usage:
swapoff -a [-v] disable all swaps
swapoff [-v] <special> disable given swap
swapoff -h display help
swapoff -V display version
The <special> parameter:
{-L label | LABEL=label} LABEL of device to be used
{-U uuid | UUID=uuid} UUID of device to be used
<device> name of device to be used
<file> name of file to be used
--在根目录下生成一个文件:swap-file,大小1G:
[iyunv@dave u01]# dd if=/dev/zero of=/swap-filebs=1M count=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 5.91518 s, 182MB/s
[iyunv@dave u01]# cd /
[iyunv@dave /]# ls
bin cgroup etc lib lost+found misc net proc sbin srv sys u01 usr
boot dev home lib64 media mnt opt root selinux swap-file tmp u02 var
[iyunv@dave /]#
--将生成的文件格式化成交换分区:
[iyunv@dave /]# mkswap /swap-file
mkswap: /swap-file: warning: don't erase bootbitssectors
onwhole disk. Use -f to force.
Setting up swapspace version 1, size = 1048572 KiB
no label, UUID=653bbeb5-4abb-4295-b110-5847e073140d
--这里没有分区的lable,只有一个UUID。
先划分一个1G的磁盘分区出来:
[iyunv@rhce /]# fdisk /dev/sdb
Device contains neither a valid DOS partitiontable, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier0x65edb587.
Changes will remain in memory only, until youdecide to write them.
After that, of course, the previous content won'tbe recoverable.
Warning: invalid flag 0x0000 of partition table 4will be corrected by w(rite)
WARNING: DOS-compatible mode is deprecated. It'sstrongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-652, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-652,default 652): +1G
Command (m for help): w
The partition table has been altered!
Disk /dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000bcd24
DeviceBoot Start End Blocks Id System
/dev/sda1 * 1 128 1024000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 128 511 3072000 82 Linux swap / Solaris
Partition 2 does not end on cylinder boundary.
/dev/sda3 511 2611 16874496 83 Linux
Disk /dev/sdb: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x65edb587
DeviceBoot Start End Blocks Id System
/dev/sdb1 1 132 1060258+ 83 Linux
…
WARNING: DOS-compatible mode is deprecated. It'sstrongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): h
h: unknown command
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition's system id
u change display/entry units
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): L
0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris
1 FAT12 39 Plan 9 82 Linux swap / So c1 DRDOS/sec (FAT-
2 XENIX root 3c PartitionMagic 83 Linux c4 DRDOS/sec (FAT-
3 XENIX usr 40 Venix 80286 84 OS/2 hidden C: c6 DRDOS/sec (FAT-
4 FAT16 <32M 41 PPC PReP Boot 85 Linux extended c7 Syrinx
5 Extended 42 SFS 86 NTFS volume set da Non-FS data
6 FAT16 4d QNX4.x 87 NTFS volume set db CP/M / CTOS /.
7 HPFS/NTFS 4e QNX4.x 2nd part 88 Linuxplaintext de Dell Utility
8 AIX 4f QNX4.x 3rd part 8e Linux LVM df BootIt
9 AIX bootable 50 OnTrack DM 93 Amoeba e1 DOS access
a OS/2 Boot Manag 51 OnTrack DM6 Aux 94 Amoeba BBT e3 DOS R/O
b W95 FAT32 52 CP/M 9f BSD/OS e4 SpeedStor
c W95 FAT32 (LBA) 53 OnTrack DM6 Aux a0 IBM Thinkpad hi eb BeOS fs
e W95 FAT16 (LBA) 54 OnTrackDM6 a5 FreeBSD ee GPT
f W95 Ext'd (LBA) 55 EZ-Drive a6 OpenBSD ef EFI (FAT-12/16/
10 OPUS 56 Golden Bow a7 NeXTSTEP f0 Linux/PA-RISC b
11 HiddenFAT12 5c Priam Edisk a8 Darwin UFS f1 SpeedStor
12 Compaqdiagnost 61 SpeedStor a9 NetBSD f4 SpeedStor
14 HiddenFAT16 <3 63 GNU HURD or Sys ab Darwin boot f2 DOS secondary
16 HiddenFAT16 64 Novell Netware af HFS/ HFS+ fb VMware VMFS
17 HiddenHPFS/NTF 65 Novell Netware b7 BSDI fs fc VMware VMKCORE
18 ASTSmartSleep 70 DiskSecure Mult b8 BSDI swap fd Linux raid auto
1b HiddenW95 FAT3 75 PC/IX bb Boot Wizard hid fe LANstep
1c HiddenW95 FAT3 80 Old Minix be Solaris boot ff BBT
1e HiddenW95 FAT1
Hex code (type L to list codes):82
Changed system type of partition1 to 82 (Linux swap / Solaris)
--注意这里更改磁盘分区的ID类型,如果不更在,在系统重启时会根据ID来判断磁盘的类型,那样在使用时就会出现错误。
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed witherror 16: Device or resource busy.
The kernel still uses the old table. The new tablewill be used at
the next reboot or after you run partprobe(8) orkpartx(8)
Syncing disks.
[iyunv@rhce ~]#
--格式化swap分区:
[iyunv@rhce /]# mkswap /dev/sdb1
Setting up swapspace version 1, size = 1060252 KiB
no label, UUID= bc913e6b-209a-49a7-b561-9b8c57294681