LINUX SWAP的檢視與維護

1.檢視SWAP

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

2.透過DD建立

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
讀入了 16382+0 個塊
輸出了 16382+0 個塊
[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

開機自動啟動：

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.直接再加一棵硬碟，並且將其中某個扇區規劃為 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: 裝置或資源忙.
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