swap空间扩容

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最新推荐文章于 2025-03-31 17:11:42 发布

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分类专栏： RHCE操作系统文章标签： swap 扩容

本文链接：https://blog.youkuaiyun.com/qq_41904732/article/details/99571479

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本文介绍了如何查看并增加Linux系统的swap空间，包括创建新的swap分区、格式化、激活以及设置优先级。通过编辑/etc/fstab文件，可以调整新分区的优先级，确保重启后生效。

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1.查看现有swap空间大小

[root@centos7 ~]# free
              total        used        free      shared  buff/cache   available
Mem:        2028116      389108     1266584       12644      372424     1424920
Swap:       2097148           0     2097148

2.添加新磁盘，并进行分区。分区类型为82（Linux swap / Solaris）
在这里插入图片描述

[root@centos7 ~]# fdisk /dev/sdb
Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0x5dfd214d.

Command (m for help): n
Partition type:
   p   primary (0 primary, 0 extended, 4 free)
   e   extended
Select (default p): p
Partition number (1-4, default 1):
First sector (2048-41943039, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): +8G
Partition 1 of type Linux and of size 8 GiB is set
Command (m for help): t
Selected partition 1
Hex code (type L to list all codes): L
 0  Empty           24  NEC DOS         81  Minix / old Lin bf  Solaris
 1  FAT12           27  Hidden NTFS Win 82  Linux swap / So c1  DRDOS/sec (FAT-
 2  XENIX root      39  Plan 9          83  Linux           c4  DRDOS/sec (FAT-
 3  XENIX usr       3c  PartitionMagic  84  OS/2 hidden C:  c6  DRDOS/sec (FAT-
 4  FAT16 <32M      40  Venix 80286     85  Linux extended  c7  Syrinx
 5  Extended        41  PPC PReP Boot   86  NTFS volume set da  Non-FS data
 6  FAT16           42  SFS             87  NTFS volume set db  CP/M / CTOS / .
 7  HPFS/NTFS/exFAT 4d  QNX4.x          88  Linux plaintext de  Dell Utility
 8  AIX             4e  QNX4.x 2nd part 8e  Linux LVM       df  BootIt
 9  AIX bootable    4f  QNX4.x 3rd part 93  Amoeba          e1  DOS access
 a  OS/2 Boot Manag 50  OnTrack DM      94  Amoeba BBT      e3  DOS R/O
 b  W95 FAT32       51  OnTrack DM6 Aux 9f  BSD/OS          e4  SpeedStor
 c  W95 FAT32 (LBA) 52  CP/M            a0  IBM Thinkpad hi eb  BeOS fs
 e  W95 FAT16 (LBA) 53  OnTrack DM6 Aux a5  FreeBSD         ee  GPT
 f  W95 Ext'd (LBA) 54  OnTrackDM6      a6  OpenBSD         ef  EFI (FAT-12/16/
10  OPUS            55  EZ-Drive        a7  NeXTSTEP        f0  Linux/PA-RISC b
11  Hidden FAT12    56  Golden Bow      a8  Darwin UFS      f1  SpeedStor
12  Compaq diagnost 5c  Priam Edisk     a9  NetBSD          f4  SpeedStor
14  Hidden FAT16 <3 61  SpeedStor       ab  Darwin boot     f2  DOS secondary
16  Hidden FAT16    63  GNU HURD or Sys af  HFS / HFS+      fb  VMware VMFS
17  Hidden HPFS/NTF 64  Novell Netware  b7  BSDI fs         fc  VMware VMKCORE
18  AST SmartSleep  65  Novell Netware  b8  BSDI swap       fd  Linux raid auto
1b  Hidden W95 FAT3 70  DiskSecure Mult bb  Boot Wizard hid fe  LANstep
1c  Hidden W95 FAT3 75  PC/IX           be  Solaris boot    ff  BBT
1e  Hidden W95 FAT1 80  Old Minix
Hex code (type L to list all codes): 82
Changed type of partition 'Linux' to 'Linux swap / Solaris'

Command (m for help): p

Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x5dfd214d

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1            2048    16779263     8388608   82  Linux swap / Solaris

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

将分区/dev/sdb1格式化为swap分区，并激活新的swap分区，然后查看swap分区大小

[root@centos7 ~]# mkswap /dev/sdb1
Setting up swapspace version 1, size = 8388604 KiB
no label, UUID=524054a2-6683-48e7-808f-8e51ac4be8ff
[root@centos7 ~]# swapon /dev/sdb1
[root@centos7 ~]# swapon -s
Filename                                Type            Size    Used    Priority
/dev/dm-1                               partition       2097148 0       -2
/dev/sdb1                               partition       8388604 0       -3
[root@centos7 ~]# free
              total        used        free      shared  buff/cache   available
Mem:        2028116      401980     1252876       12644      373260     1412424
Swap:      10485752           0    10485752

如果要/dev/sdb1分区每次优先使用，可编辑/etc/fstab文件，将此分区的优先级改为1，修改完成后需重启机器才会生效

[root@centos7 ~]# vi /etc/fstab
[root@centos7 ~]# cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Tue Aug 13 23:27:51 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root /                       xfs     defaults        0 0
UUID=18170546-e5ce-4fd1-9f7a-45df40e45621 /boot                   xfs     defaults        0 0
/dev/mapper/centos-swap swap                    swap    defaults        0 0
/dev/sdb1               swap                    swap    defaults,pri=1  0 0

[root@centos7 ~]# reboot
[root@centos7 ~]# swapon -s
Filename                                Type            Size    Used    Priority
/dev/sdb1                               partition       8388604 0       1
/dev/dm-1                               partition       2097148 0       -2