Linux LVM逻辑卷管理及扩容（二）

四、LVM扩展逻辑卷

我们当如何对lvm扩容呢，在vg组有空余的空间时，可以lvextend增加空间；在vg组无空间时，可以通过先增加pv，再lvextend实现扩容

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 [root@localhost ~]# lvextend -L +300m /dev/libo/X
 Size of logical volume libo/X changed from 1.50 GiB (384 extents) to 1.79 GiB (459 extents).
 Logical volume X successfully resized.
 [root@localhost ~]# vgextend libo /dev/sdb3
 Volume group "libo" successfully extended

我们把LVM逻辑卷管理及扩容（一）中创建的四个分区全部都添加给lvm X，大小为4G

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 [root@localhost ~]# lvextend -L +2g /dev/libo/X
 Size of logical volume libo/X changed from 1.79 GiB (459 extents) to 3.79 GiB (971 extents).
 Logical volume X successfully resized.
 [root@localhost ~]# lvdisplay x
 Volume group "x" not found
 Cannot process volume group x
 [root@localhost ~]# lvdisplay /dev/libo/X
 --- Logical volume ---
 LV Path /dev/libo/X
 LV Name X
 VG Name libo
 LV UUID fpyvTb-f1Wd-OVek-5h05-3U19-gLmQ-2sBMF8
 LV Write Access read/write
 LV Creation host, time localhost.localdomain, 2016-04-26 12:33:53 +0800
 LV Status available
 # open 1
 LV Size 3.79 GiB
 Current LE 971
 Segments 4
 Allocation inherit
 Read ahead sectors auto
 - currently set to 8192
 Block device 253:2

通过xfs_growfs对lvm进行扩容 xfs_growfs -d /dev/libo/X

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 [root@localhost ~]# xfs_growfs -d /dev/libo/X
 meta-data=/dev/mapper/libo-X isize=256 agcount=4, agsize=98304 blks
 = sectsz=512 attr=2, projid32bit=1
 = crc=0 finobt=0
 data = bsize=4096 blocks=393216, imaxpct=25
 = sunit=0 swidth=0 blks
 naming =version 2 bsize=4096 ascii-ci=0 ftype=0
 log =internal bsize=4096 blocks=2560, version=2
 = sectsz=512 sunit=0 blks, lazy-count=1
 realtime =none extsz=4096 blocks=0, rtextents=0
 data blocks changed from 393216 to 996352
 [root@localhost ~]# df -h
 Filesystem Size Used Avail Use% Mounted on
 /dev/mapper/rhel-root 20G 3.7G 17G 19% /
 devtmpfs 898M 0 898M 0% /dev
 tmpfs 913M 84K 913M 1% /dev/shm
 tmpfs 913M 9.1M 904M 1% /run
 tmpfs 913M 0 913M 0% /sys/fs/cgroup
 /dev/sda3 1014M 33M 982M 4% /163
 /dev/sr0 3.8G 3.8G 0 100% /mnt
 /dev/md5 2.0G 33M 2.0G 2% /md5
 /dev/sda1 797M 165M 633M 21% /boot
 tmpfs 183M 16K 183M 1% /run/user/42
 tmpfs 183M 0 183M 0% /run/user/0
 /dev/mapper/libo-X 3.8G 33M 3.8G 1% /lvm

五、LVM缩减逻辑卷

当硬盘空间在某种情况下，如果减少逻辑卷的空间释放给其他逻辑卷使用。我们可以通过lvreduce 缩减或是vgreduce缩减
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 [root@localhost ~]# lvs
 LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
 x libo -wi-a----- 3.90g
 root rhel -wi-ao---- 20.00g
 swap rhel -wi-ao---- 2.00g
 [root@localhost ~]# lvreduce -L 2g /dev/libo/x              #-L 2g 表示把lvm缩减到2g，不是减少2g
 WARNING: Reducing active logical volume to 2.00 GiB
 THIS MAY DESTROY YOUR DATA (filesystem etc.)
 Do you really want to reduce x? [y/n]: y
 Size of logical volume libo/x changed from 3.90 GiB (999 extents) to 2.00 GiB (512 extents).
 Logical volume x successfully resized.
 [root@localhost ~]# lvs
 LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
 x libo -wi-a----- 2.00g
 root rhel -wi-ao---- 20.00g
 swap rhel -wi-ao---- 2.00g
 [root@localhost ~]# vgreduce libo /dev/sdb4 Removed "/dev/sdb4" from volume group "libo"
 [root@localhost ~]# pvs   PV         VG   Fmt  Attr PSize    PFree      /dev/sda2  rhel lvm2 a--    22.00g    4.00m   /dev/sdb1  libo lvm2 a--  1020.00m       0    /dev/sdb2  libo lvm2 a--  1020.00m       0    /dev/sdb3  libo lvm2 a--  1020.00m 1012.00m   /dev/sdb4       lvm2 ---     1.00g    1.00g

六、lvm删除、vg删除、pv删除

在删除lvm前，需要卸载挂载的分区
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 [root@localhost ~]# lvremove /dev/libo/x
 Do you really want to remove active logical volume x? [y/n]: y
 Logical volume "x" successfully removed
 [root@localhost ~]# lvs
 LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
 root rhel -wi-ao---- 20.00g
 swap rhel -wi-ao---- 2.00g
 [root@localhost ~]# vgremove libo
 Volume group "libo" successfully removed
 [root@localhost ~]# vgs
 VG #PV #LV #SN Attr VSize VFree
 rhel 1 2 0 wz--n- 22.00g 4.00m
 [root@localhost ~]# pvremove /dev/sdb{1..4}
 Labels on physical volume "/dev/sdb1" successfully wiped
 Labels on physical volume "/dev/sdb2" successfully wiped
 Labels on physical volume "/dev/sdb3" successfully wiped
 Labels on physical volume "/dev/sdb4" successfully wiped
 [root@localhost ~]# pvs
 PV VG Fmt Attr PSize PFree
 /dev/sda2 rhel lvm2 a-- 22.00g 4.00m
 [root@localhost ~]#

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