系统安装之后创建swap
创建swap分区
[root@localhost cdrom]# fdisk /dev/sdc
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won't be recoverable.
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)
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
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): l
#查看swap使用的系统编号
0 Empty
1e Hidden W95 FAT1 80 Old Minix be Solaris boot
1 FAT12
24 NEC DOS 81 Minix / old Lin bf Solaris
2 XENIX root
39 Plan 9 82 Linux swap / So c1 DRDOS/sec (FAT-
3 XENIX usr
3c PartitionMagic 83 Linux c4 DRDOS/sec (FAT-
4 FAT16 <32M
40 Venix 80286 84 OS/2 hidden C: c6 DRDOS/sec (FAT-
5 Extended
41 PPC PReP Boot 85 Linux extended c7 Syrinx
6 FAT16
42 SFS 86 NTFS volume set da Non-FS data
7 HPFS/NTFS
4d QNX4.x 87 NTFS volume set db CP/M / CTOS / .
8 AIX
4e QNX4.x 2nd part 88 Linux plaintext 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 75 PC/IX
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-1044, default 1):
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-1044, default 1044): +2048M
Command (m for help): t
修改系统id
Selected partition 1
Hex code (type L to list codes): 82
id82指的是swap系统
Changed system type of partition 1 to 82 (Linux swap / Solaris)
Command (m for help): p
Disk /dev/sdc: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdc1
1 250 2008093+ 82 Linux swap / Solaris
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@localhost cdrom]# partprobe
#讥核心更新 partition table
Warning: Unable to open /dev/hdc read-write (Read-only file system). /dev/hdc has been opened read-only.
格式swap
[root@localhost cdrom]# mkswap /dev/sdc1
Setting up swapspace version 1, size = 2056282 kB
加载swap，并查看效果
[root@localhost cdrom]# free #查看默认的
total used free shared buffers cached
Mem:
515600 493728 21872 0 4476 334584
-/+ buffers/cache:
154668 360932
Swap:
1048568 72 1048496
[root@localhost cdrom]# swapon /dev/sdc1
[root@localhost cdrom]# free
#查看效果
total used free shared buffers cached
Mem:
515600 494852 20748 0 4536 334612
-/+ buffers/cache:
155704 359896
Swap:
3056652 72 3056580
[root@localhost cdrom]# swapon –s
#查看
Filename
Type Size Used Priority
/dev/mapper/VolGroup00-LogVol01
partition 1048568 72 -1
/dev/sdc1
partition 2008084 0 -2
另一种建立swap文件的方法实现
首先使用dd命令创建一个swap的文档
[root@localhost cdrom]# dd if=/dev/zero of=/tmp/swap bs=1M count=128
128+0 records in
128+0 records out
134217728 bytes (134 MB) copied, 0.819607 seconds, 164 MB/s
格式化文档
[root@localhost cdrom]# mkswap /tmp/swap
Setting up swapspace version 1, size = 134213 kB
查看现有的内存
[root@localhost cdrom]# free
total used free shared buffers cached
Mem:
515600 504896 10704 0 5468 343504
-/+ buffers/cache:
155924 359676
Swap:
3056652 72 3056580
启动/tmp/swap文件
[root@localhost cdrom]# swapon /tmp/swap
[root@localhost cdrom]# free
total used free shared buffers cached
Mem:
515600 505012 10588 0 5484 343508
-/+ buffers/cache:
156020 359580
Swap:
3187716 72 3187644
查看开启的内存文档
[root@localhost cdrom]# swapon -s
Filename
Type Size Used Priority
/dev/mapper/VolGroup00-LogVol01
partition 1048568 72 -1
/dev/sdc1
partition 2008084 0 -2
/tmp/swap
file 131064 0 -3
关闭内存文件
[root@localhost cdrom]# swapoff /dev/sdc1
[root@localhost cdrom]# swapoff /tmp/swap
[root@localhost cdrom]# free
total used free shared buffers cached
Mem:
515600 503896 11704 0 5512 343508
-/+ buffers/cache:
154876 360724
Swap:
1048568 72 1048496
[root@localhost cdrom]#