LVM擴縮--lvm縮小swap，根分區在線擴容

因爲系統部署的時候，分區使用的默認分區管理，系統規劃不是很好，swap過於大，浪費了不少磁盤空間，這裏講將swap下線，進行縮容，而後將縮減出的容量補充到在線的根分區上。當然只有一個根分區很差，這樣規劃之後會出一些問題，這裏只討論操做的擴縮的操做步驟。

下文中，紅色加粗字體的部分是操做的命令，藍色部分是須要特別注意的地方。經過這些藍色的輸出來肯定你的服務器該怎麼調整容量大小，而且檢查是否達到調整的預期。

思路：首先查看swap的大小及分區，而後調整swap大小，使vg中有空餘的空間能夠給根分區的lv進行補充。而後重建swap，掛載swap，檢查vg的空餘容量顯示是否正常，而後給根分區的lv擴容，resize2fs，完成。

此操做爲真實線上服務器的調整記錄，供朋友們參考，在真實上線操做以前，請務必在與你在的平臺徹底相同的實驗環境進行詳細的測試，而後方可實施操做。個人系統環境是：

操做系統：RHEL 5u3 64bit

內核版本：2.6.18-128.el5

[root@server10 ~]# free -g
             total       used       free     shared    buffers     cached
Mem:            62         62          0          0          0         60
-/+ buffers/cache:          2         60
Swap:          127          0        127
[root@server10 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                      147G   74G   65G  54% /
/dev/sda1              99M   13M   81M  14% /boot
tmpfs                  32G     0   32G   0% /dev/shm
[root@server10 ~]# cat /etc/fstab
/dev/VolGroup00/LogVol00 /                       ext3    defaults        1 1
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
/dev/VolGroup00/LogVol01 swap                    swap    defaults        0 0
[root@server10 ~]# lvdisplay
  --- Logical volume ---
  LV Name                /dev/VolGroup00/LogVol00
  VG Name                VolGroup00
  LV UUID                oZ7rEm-hphT-MsGk-fNaD-RC5X-INgZ-oCJdml
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                150.84 GB
  Current LE             4827
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0
  
  --- Logical volume ---
  LV Name                /dev/VolGroup00/LogVol01
  VG Name                VolGroup00
  LV UUID                pCpqVB-cwXV-MunF-OtBQ-usYA-hFxt-l07IJc
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                127.91 GB
  Current LE             4093
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:1
  
[root@server10 ~]# vgdisplay
  --- Volume group ---
  VG Name               VolGroup00
  System ID            
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  3
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               278.75 GB
  PE Size               32.00 MB
  Total PE              8920
  Alloc PE / Size       8920 / 278.75 GB
  Free  PE / Size       0 / 0  
  VG UUID               9hHRZZ-VUd4-bMwc-rnhK-wiyq-sPZw-dtJREo  
[root@server10 ~]# free -m
             total       used       free     shared    buffers     cached
Mem:         64449      64129        320          0        327      61494
-/+ buffers/cache:       2307      62142
Swap:       130975          0     130975
[root@server10 ~]# swapoff -a
[root@server10 ~]# free -m
             total       used       free     shared    buffers     cached
Mem:         64449      64065        384          0        327      61494
-/+ buffers/cache:       2243      62206
Swap:            0          0          0
[root@server10 ~]# lvreduce /dev/VolGroup00/LogVol01 -L -64G
  WARNING: Reducing active logical volume to 63.91 GB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce LogVol01? [y/n]: y
  Reducing logical volume LogVol01 to 63.91 GB
  Logical volume LogVol01 successfully resized
[root@server10 ~]# mkswap /dev/VolGroup00/LogVol01
Setting up swapspace version 1, size = 68618809 kB
[root@server10 ~]# swapon /dev/VolGroup00/LogVol01
[root@server10 ~]# free -m
             total       used       free     shared    buffers     cached
Mem:         64449      64150        299          0        327      61549
-/+ buffers/cache:       2273      62175
Swap:        65439          0      65439
[root@server10 ~]# free -g
             total       used       free     shared    buffers     cached
Mem:            62         62          0          0          0         60
-/+ buffers/cache:          2         60
Swap:           63          0         63
[root@server10 ~]# vgdisplay
  --- Volume group ---
  VG Name               VolGroup00
  System ID            
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               278.75 GB
  PE Size               32.00 MB
  Total PE              8920
  Alloc PE / Size       6872 / 214.75 GB
  Free  PE / Size       2048 / 64.00 GB
  VG UUID               9hHRZZ-VUd4-bMwc-rnhK-wiyq-sPZw-dtJREo
  
[root@server10 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                      147G   74G   65G  54% /
/dev/sda1              99M   13M   81M  14% /boot
tmpfs                  32G     0   32G   0% /dev/shm
[root@server10 ~]# mount
/dev/mapper/VolGroup00-LogVol00 on / type ext3 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/sda1 on /boot type ext3 (rw)
tmpfs on /dev/shm type tmpfs (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
[root@server10 ~]# lvextend /dev/VolGroup00/LogVol00 -l +100%FREE
  Extending logical volume LogVol00 to 214.84 GB
  Logical volume LogVol00 successfully resized
[root@server10 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                      147G   74G   65G  54% /
/dev/sda1              99M   13M   81M  14% /boot
tmpfs                  32G     0   32G   0% /dev/shm
[root@server10 ~]# resize2fs /dev/VolGroup00/LogVol00
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/VolGroup00/LogVol00 is mounted on /; on-line resizing required
Performing an on-line resize of /dev/VolGroup00/LogVol00 to 56320000 (4k) blocks.
The filesystem on /dev/VolGroup00/LogVol00 is now 56320000 blocks long.

[root@server10 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                      209G   74G  124G  38% /
/dev/sda1              99M   13M   81M  14% /boot
tmpfs                  32G     0   32G   0% /dev/shm
[root@server10 ~]#