LVM: 为/ 从swap中偷空间

原因： root(/)分区只有5.4G，并已经100%被用。而swap分区有2G空间，大多数时候并没用到。

背景：Centos 默认安装，root和swap 都被置于LVM管理，并且他们属于同一个VG（Volume Group）

[root@l-shc-00425594 ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup00-LogVol00                       5.4G 5.4G 0 100% / /dev/hda1 487M 27M 435M 6% /boot tmpfs 225M 0 225M 0% /dev/shm /dev/hdb1 5.0G 1.1G 3.7G 23% /vendor none 225M 104K 225M 1% /var/lib/xenstored /dev/hdc 57M 57M 0 100% /media/CDROM [root@l-shc-00425594 ~]# fdisk -l Disk /dev/hda: 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/hda1 * 1 64 514048+ 83 Linux /dev/hda2 65 1044 7871850 8e Linux LVM Disk /dev/hdb: 7516 MB, 7516192768 bytes 16 heads, 63 sectors/track, 14563 cylinders Units = cylinders of 1008 * 512 = 516096 bytes    Device Boot Start End Blocks Id System /dev/hdb1 1 10402 5242576+ 83 Linux [root@l-shc-00425594 ~]# lvdisplay   --- Logical volume ---   LV Name /dev/VolGroup00/LogVol00   VG Name VolGroup00   LV UUID nt2aLV-i3Rl-vDvT-zDog-0ccW-CPT1-tUSTK3   LV Write Access read/write   LV Status available   # open 1   LV Size 5.50 GB   Current LE 176   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 fIwop8-uT2t-DsLK-Rxqg-Z8r4-7hzu-m16TCl   LV Write Access read/write   LV Status available   # open 1   LV Size 2.00 GB   Current LE 64   Segments 1   Allocation inherit   Read ahead sectors auto   - currently set to 256   Block device 253:1     [root@l-shc-00425594 ~]# cat /proc/swaps Filename Type Size Used Priority /dev/mapper/VolGroup00-LogVol01 partition 2097144 0 -1 [root@l-shc-00425594 ~]# swapoff -v /dev/mapper/VolGroup00-LogVol01 swapoff on /dev/mapper/VolGroup00-LogVol01 [root@l-shc-00425594 ~]# lvm lvreduce /dev/mapper/VolGroup00-LogVol01 -L 1G   /dev/hdc: open failed: Read-only file system   WARNING: Reducing active logical volume to 1.00 GB   THIS MAY DESTROY YOUR DATA (filesystem etc.) Do you really want to reduce LogVol01? [y/n]: y   Reducing logical volume LogVol01 to 1.00 GB   Logical volume LogVol01 successfully resized [root@l-shc-00425594 ~]# lvm lvreduce /dev/mapper/VolGroup00-LogVol01 -L -512M   /dev/hdc: open failed: Read-only file system   WARNING: Reducing active logical volume to 512.00 MB   THIS MAY DESTROY YOUR DATA (filesystem etc.) Do you really want to reduce LogVol01? [y/n]: y   Reducing logical volume LogVol01 to 512.00 MB   Logical volume LogVol01 successfully resized [root@l-shc-00425594 ~]# mkswap /dev/mapper/VolGroup00-LogVol01 Setting up swapspace version 1, size = 536866 kB [root@l-shc-00425594 ~]# swapon -va swapon on /dev/VolGroup00/LogVol01 [root@l-shc-00425594 ~]# cat /proc/swaps Filename Type Size Used Priority /dev/mapper/VolGroup00-LogVol01 partition 524280 0 -2 [root@l-shc-00425594 ~]# free -m              total used free shared buffers cached Mem: 450 418 31 0 25 272 -/+ buffers/cache: 120 329 Swap: 511 0 511 [root@l-shc-00425594 ~]# lvextend -L +1.5G /dev/mapper/VolGroup00-LogVol0 VolGroup00-LogVol00 VolGroup00-LogVol01 [root@l-shc-00425594 ~]# lvextend -L +1.5G /dev/mapper/VolGroup00-LogVol00   /dev/hdc: open failed: Read-only file system   Extending logical volume LogVol00 to 7.00 GB   Logical volume LogVol00 successfully resized [root@l-shc-00425594 ~]# resize2fs /dev/mapper/VolGroup00-LogVol0 VolGroup00-LogVol00 VolGroup00-LogVol01 [root@l-shc-00425594 ~]# resize2fs /dev/mapper/VolGroup00-LogVol00 resize2fs 1.39 (29-May-2006) Filesystem at /dev/mapper/VolGroup00-LogVol00 is mounted on /; on-line resizing required Performing an on-line resize of /dev/mapper/VolGroup00-LogVol00 to 1835008 (4k) blocks. The filesystem on /dev/mapper/VolGroup00-LogVol00 is now 1835008 blocks long. [root@l-shc-00425594 ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup00-LogVol00                       6.8G 5.4G 1.2G 83% / /dev/hda1 487M 27M 435M 6% /boot tmpfs 225M 0 225M 0% /dev/shm /dev/hdb1 5.0G 1.1G 3.7G 23% /vendor none 225M 104K 225M 1% /var/lib/xenstored /dev/hdc 57M 57M 0 100% /media/CDROM