RH134小结(八)LVM增大和减小ext4、xfs分区

在之前 LVM分区无损增减 篇中有提到过LVM分区的无损增大和减小,不同的是,当是只是针对LVM下的ext分区的,在新版的RHEL7/centos7中默认使用的分区格式是xfs ,本篇就针对LVM下ext4和xfs分区的增大和缩小再唠叨下。

一、ext4分区下LVM的动态调整

在使用lvresize调整大小时结常需要注意与resize2fs执行的顺序。缩小空间时,一定要先执行resize2fs再执行lvresize;而增大时一定要先执行lvextend再执行resize2fs 。

1、减小大小

减小LVM分区时,一定要先umount掉挂载点再进行操作。

[root@361way.com ~]# df -H /mnt/
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg-lvol0  805M  2.7M  760M   1% /mnt
[root@361way.com ~]# umount /mnt/
[root@361way.com ~]# resize2fs -f /dev/vg/lvol0 100M
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/vg/lvol0 to 102400 (1k) blocks.
The filesystem on /dev/vg/lvol0 is now 102400 blocks long.
[root@361way.com ~]# lvresize -L 100M /dev/vg/lvol0
  WARNING: Reducing active logical volume to 100.00 MiB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce lvol0? [y/n]: y
  Size of logical volume vg/lvol0 changed from 800.00 MiB (200 extents) to 100.00 MiB (25 extents).
  Logical volume lvol0 successfully resized
[root@361way.com ~]# mount /dev/vg/lvol0 /mnt/
[root@361way.com ~]# df -H /mnt/
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg-lvol0   94M  1.6M   87M   2% /mnt
[root@361way.com ~]# 

2、增大空间

[root@361way.com ~]# lvextend -L 800M /dev/vg/lvol0
  Size of logical volume vg/lvol0 changed from 100.00 MiB (25 extents) to 800.00 MiB (200 extents).
  Logical volume lvol0 successfully resized
[root@361way.com ~]# resize2fs -f /dev/vg/lvol0
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/vg/lvol0 is mounted on /mnt; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 4
Performing an on-line resize of /dev/vg/lvol0 to 819200 (1k) blocks.
The filesystem on /dev/vg/lvol0 is now 819200 blocks long.
[root@361way.com ~]# df -H /mnt/
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg-lvol0  805M  2.7M  761M   1% /mnt

3、一个命令搞定增大和减小

一会儿是增大,一会儿是减小,搞不好很容易搞错并造成分区损坏、数据受损,有没有不管增大减小一个命令全搞定的方法?当然有lvresize命令里有一个-r选项,该选项的作用是在执行lvresize命令的时候一并执行resize2fs ,强烈推荐该方法

[root@361way.com ~]# df -H /mnt/
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg-lvol0  805M  2.7M  761M   1% /mnt
[root@361way.com ~]# lvresize -L 300M -r /dev/vg/lvol0   -->注意此处的指定,增大时同样使用该指令
Do you want to unmount "/mnt"? [Y|n] y
fsck from util-linux-ng 2.17.2
/dev/mapper/vg-lvol0: 11/203200 files (0.0% non-contiguous), 36387/819200 blocks
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/mapper/vg-lvol0 to 307200 (1k) blocks.
The filesystem on /dev/mapper/vg-lvol0 is now 307200 blocks long.
  Size of logical volume vg/lvol0 changed from 800.00 MiB (200 extents) to 300.00 MiB (75 extents).
  Logical volume lvol0 successfully resized
[root@361way.com ~]#
[root@361way.com ~]# df -H /mnt/
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg-lvol0  297M  2.2M  279M   1% /mnt

上面已经由800M 减小到了300M,而且更神奇的是,减小前我并没有umount分区,它自动提示让我们umount掉。此处使用同样的指令增大到500M 。

[root@361way.com ~]# lvresize -L 500M -r /dev/vg/lvol0
  Size of logical volume vg/lvol0 changed from 300.00 MiB (75 extents) to 500.00 MiB (125 extents).
  Logical volume lvol0 successfully resized
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mapper/vg-lvol0 is mounted on /mnt; on-line resizing required
old desc_blocks = 2, new_desc_blocks = 2
Performing an on-line resize of /dev/mapper/vg-lvol0 to 512000 (1k) blocks.
The filesystem on /dev/mapper/vg-lvol0 is now 512000 blocks long.
[root@361way.com ~]# df -H /mnt/
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg-lvol0  500M  2.4M  472M   1% /mnt

见证到奇迹了吧,就是这么任性。

二、XFS分区

xfs分区是不支持减小操作的,这点挺蛋疼。我们先当做不知道该特性,同lvresize -r 指定试下,结果如下:

# lvresize -L 50M /dev/vg2/xfstest -r
Phase 1 - find and verify superblock...
Phase 2 - using internal log
        - scan filesystem freespace and inode maps...
        - found root inode chunk
Phase 3 - for each AG...
        - scan (but don't clear) agi unlinked lists...
        - process known inodes and perform inode discovery...
        - agno = 0
        - agno = 1
        - agno = 2
        - agno = 3
        - agno = 4
        - process newly discovered inodes...
Phase 4 - check for duplicate blocks...
        - setting up duplicate extent list...
        - check for inodes claiming duplicate blocks...
        - agno = 0
        - agno = 1
        - agno = 2
        - agno = 3
        - agno = 4
No modify flag set, skipping phase 5
Phase 6 - check inode connectivity...
        - traversing filesystem ...
        - traversal finished ...
        - moving disconnected inodes to lost+found ...
Phase 7 - verify link counts...
No modify flag set, skipping filesystem flush and exiting.
fsadm: Xfs filesystem shrinking is unsupported   -->看到相关信息了,不好意思,xfs不支持
  fsadm failed: 1
  Filesystem resize failed.

增大看下:

# df -Th /mnt
Filesystem                 Type  Size  Used Avail Use% Mounted on
/dev/mapper/vg2-xfstest xfs    97M  5.3M   92M   6% /mnt
先使用lvextend增大LVM分区的大小
# lvextend -L 120M /dev/vg2/xfstest
  Extending logical volume vo to 120.00 MiB
  Logical volume vo successfully resized
再使用xfs_growfs在物理分区上调整
# xfs_growfs /dev/vg2/xfstest
meta-data=/dev/mapper/vg2-xfstest isize=256    agcount=5, agsize=5120 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=0
data     =                       bsize=4096   blocks=25600, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=0
log      =internal               bsize=4096   blocks=853, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 25600 to 30720
# df -Th /mnt
Filesystem                 Type  Size  Used Avail Use% Mounted on
/dev/mapper/vg2-xfstest xfs    117M  5.3M   92M   6% /mnt




本站的发展离不开您的资助,金额随意,欢迎来赏!

You can donate through PayPal.
My paypal id: itybku@139.com
Paypal page: https://www.paypal.me/361way

分类: Linux/unix/mac 标签: ,
  1. 本文目前尚无任何评论.
  1. 本文目前尚无任何 trackbacks 和 pingbacks.