LINUX的交换分区或交换文件SWAP的查看与维护

1.查看SWAP
[root@rose /]# cat /proc/swaps
Filename Type Size Used Priority
/dev/sdb1 partition 2096440 8 -1
/tmp/swap file 65520 0 -3

2.通过DD创建

boot etc initrd lost+found misc opt root selinux sys test1 usr
[root@rose /]# dd if=/dev/zero f=/tmp/swap bs=4k count=16382
读入了 16382+0 个块
输出了 16382+0 个块
[root@rose /]# mkswap /tmp/swap
Setting up swapspace version 1, size = 67096 kB
[root@rose /]# free
total used free shared buffers cached
Mem: 384704 364624 20080 0 17180 305472
-/+ buffers/cache: 41972 342732
Swap: 2096440 8 2096432

swapon [-s]
[root@rose /]# swapon /tmp/swap
[root@rose /]# free
total used free shared buffers cached
Mem: 384704 364560 20144 0 17196 305456
-/+ buffers/cache: 41908 342796
Swap: 2161960 8 2161952

开机自动启动：

LABEL=/ / ext3 defaults 1 1
LABEL=/home /home ext3 defaults 1 2
LABEL=/var /var ext3 defaults 1 2
LABEL=/tmp /tmp ext3 defaults 1 2
LABEL=/usr /usr ext3 defaults 1 2
LABEL=/boot /boot ext3 defaults 1 2
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
LABEL=SWAP swap swap defaults 0 0
/home/swap swap swap defaults 0 0

3.直接再加一棵硬盘，并且将其中某个扇区规划为 swap 的 filesystem

[root@rose /]# fdisk /dev/sdc

The number of cylinders for this disk is set to 1044.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): t
Partition number (1-5): 3
Hex code (type L to list codes): L

0 Empty 1e Hidden W95 FAT1 75 PC/IX be Solaris boot
1 FAT12 24 NEC DOS 80 Old Minix bf Solaris
2 XENIX root 39 Plan 9 81 Minix / old Lin c1 DRDOS/sec (FAT-
3 XENIX usr 3c PartitionMagic 82 Linux swap c4 DRDOS/sec (FAT-
4 FAT16 <32M 40 Venix 80286 83 Linux c6 DRDOS/sec (FAT-
5 Extended 41 PPC PReP Boot 84 OS/2 hidden C: c7 Syrinx
6 FAT16 42 SFS 85 Linux extended da Non-FS data
7 HPFS/NTFS 4d QNX4.x 86 NTFS volume set db CP/M / CTOS / .
8 AIX 4e QNX4.x 2nd part 87 NTFS volume set de Dell Utility
9 AIX bootable 4f QNX4.x 3rd part 8e Linux LVM df BootIt
a OS/2 Boot Manag 50 OnTrack DM 93 Amoeba e1 DOS access
b W95 FAT32 51 OnTrack DM6 Aux 94 Amoeba BBT e3 DOS R/O
c W95 FAT32 (LBA) 52 CP/M 9f BSD/OS e4 SpeedStor
e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a0 IBM Thinkpad hi eb BeOS fs
f W95 Ext'd (LBA) 54 OnTrackDM6 a5 FreeBSD ee EFI GPT
10 OPUS 55 EZ-Drive a6 OpenBSD ef EFI (FAT-12/16/
11 Hidden FAT12 56 Golden Bow a7 NeXTSTEP f0 Linux/PA-RISC b
12 Compaq diagnost 5c Priam Edisk a8 Darwin UFS f1 SpeedStor
14 Hidden FAT16 <3 61 SpeedStor a9 NetBSD f4 SpeedStor
16 Hidden FAT16 63 GNU HURD or Sys ab Darwin boot f2 DOS secondary
17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs fd Linux raid auto
18 AST SmartSleep 65 Novell Netware b8 BSDI swap fe LANstep
1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid ff BBT
1c Hidden W95 FAT3
Hex code (type L to list codes): 82
Changed system type of partition 3 to 82 (Linux swap)

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 with error 16: 设备或资源忙.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.

[root@rose /]# mkswap /dev/sdc3
Setting up swapspace version 1, size = 329007 kB
[root@rose /]# swapon /dev/sdc3