注：linux swap分区 采用lvm管理，调控可以采用下面的方法

一.查看 swap    lv

[root@testdb ~]# vgdisplay -v

Finding all volume groups

Finding volume group "VolGroup"

--- Volume group ---

VG Name               VolGroup

System ID

Format                lvm2

Metadata Areas        1

Metadata Sequence No  4

VG Access             read/write

VG Status             resizable

MAX LV                0

Cur LV                3

Open LV               3

Max PV                0

Cur PV                1

Act PV                1

VG Size               357.38 GiB

PE Size               4.00 MiB

Total PE              91489

Alloc PE / Size       34512 / 134.81 GiB

 Free  PE / Size       56977 / 222.57 GiB

VG UUID               q6q2yf-Isfw-DnkL-JeSN-uTvC-l5m2-M0HEco

--- Logical volume ---

LV Path                /dev/VolGroup/lv_root

LV Name                lv_root

VG Name                VolGroup

LV UUID                0nFC6x-BsP2-7w0r-8bPV-Vw9j-whIz-EWj5Ba

LV Write Access        read/write

LV Creation host, time localhost.localdomain, 2013-09-16 08:41:58 +0800

LV Status              available

# open                 1

LV Size                29.30 GiB

Current LE             7500

Segments               1

Allocation             inherit

Read ahead sectors     auto

- currently set to     256

Block device           252:0

 --- Logical volume ---

 LV Path                /dev/VolGroup/lv_swap

 LV Name                lv_swap

 VG Name                VolGroup

 LV UUID                OJaxbf-MPay-cjep-L44c-UKDx-ZmGW-v24yUf

 LV Write Access        read/write

 LV Creation host, time localhost.localdomain, 2013-09-16 08:42:00 +0800

 LV Status              available

 # open                 2

 LV Size                7.86 GiB

 Current LE             2012

 Segments               1

 Allocation             inherit

 Read ahead sectors     auto

 - currently set to     256

 Block device           252:1

--- Logical volume ---

LV Path                /dev/VolGroup/lv_home

LV Name                lv_home

VG Name                VolGroup

LV UUID                HZvOuv-G8NW-2ZyW-3Ffl-H54i-Kmjp-8ndVqo

LV Write Access        read/write

LV Creation host, time localhost.localdomain, 2013-09-16 08:42:01 +0800

LV Status              available

# open                 1

LV Size                97.66 GiB

Current LE             25000

Segments               1

Allocation             inherit

Read ahead sectors     auto

- currently set to     256

Block device           252:2

--- Physical volumes ---

PV Name               /dev/sda2

PV UUID               gQvj3L-kOPV-LILA-KPnD-a8W9-lgdE-09vtlQ

PV Status             allocatable

Total PE / Free PE    91489 / 56977

  

 swap  分区 lv   为/dev/VolGroup/lv_swap

二.扩大swap分区

关闭交换分区

[root@testdb ~]# swapoff /dev/VolGroup/lv_swap

[root@testdb ~]# free -m

total       used       free     shared    buffers     cached

Mem:         16081      14682       1398          0         83      13680

-/+ buffers/cache:        919      15162

Swap:            0          0          0

扩展    /dev/VolGroup/lv_swap，增加8336M

[root@testdb ~]# lvextend -L +8336M /dev/VolGroup/lv_swap

Extending logical volume lv_swap to 16.28 GiB

Logical volume lv_swap successfully resized

将 /dev/VolGroup/lv_swap 设置为swap分区

[root@testdb ~]# mkswap /dev/VolGroup/lv_swap

mkswap: /dev/VolGroup/lv_swap: warning: don't erase bootbits sectors

on whole disk. Use -f to force.

Setting up swapspace version 1, size = 17072124 KiB

no label, UUID=f5fa0e85-da9e-440c-8f1c-e3ab978c9d6b

[root@testdb ~]# free -m

total       used       free     shared    buffers     cached

Mem:         16081      14683       1398          0         83      13680

-/+ buffers/cache:        918      15162

Swap:            0          0          0

启动swap分区

[root@testdb ~]# swapon /dev/VolGroup/lv_swap

[root@testdb ~]# free -m

total       used       free     shared    buffers     cached

Mem:         16081      14695       1386          0         83      13680

-/+ buffers/cache:        931      15150

Swap:        16671          0      16671

三.减小swap分区

关闭交换分区

[root@testdb ~]# swapoff /dev/VolGroup/lv_swap

[root@testdb ~]# free -m

total       used       free     shared    buffers     cached

Mem:         16081      15141        940          0        255      13953

-/+ buffers/cache:        932      15149

Swap:            0          0          0

减小  /dev/VolGroup/lv_swap  8000M

[root@testdb ~]# lvreduce -L -8000M /dev/VolGroup/lv_swap

WARNING: Reducing active logical volume to 8.47 GiB

THIS MAY DESTROY YOUR DATA (filesystem etc.)

Do you really want to reduce lv_swap? [y/n]: y

Reducing logical volume lv_swap to 8.47 GiB

Logical volume lv_swap successfully resized

[root@testdb ~]# free -m

total       used       free     shared    buffers     cached

Mem:         16081      15143        938          0        256      13955

-/+ buffers/cache:        931      15149

Swap:            0          0          0

将 /dev/VolGroup/lv_swap 设置为swap分区

[root@testdb ~]# mkswap /dev/VolGroup/lv_swap

mkswap: /dev/VolGroup/lv_swap: warning: don't erase bootbits sectors

on whole disk. Use -f to force.

Setting up swapspace version 1, size = 8880124 KiB

no label, UUID=1951f318-e2eb-45d5-b1ed-25a2bf87adea

[root@testdb ~]# free -m

total       used       free     shared    buffers     cached

Mem:         16081      15142        938          0        256      13955

-/+ buffers/cache:        931      15150

Swap:            0          0          0

开启swap分区

[root@testdb ~]# swapon /dev/VolGroup/lv_swap

[root@testdb ~]# free -m

total       used       free     shared    buffers     cached

Mem:         16081      15149        932          0        256      13955

-/+ buffers/cache:        937      15143

Swap:         8671          0       8671

[root@testdb ~]#