Page index:
Overview
Setup Physical Volumes
Setup Volume Groups
Setup Logical Volume Group
Extending Volume Group
Extending Logical Volume
Reducing Logical Volume
Page 7 of 7
Reducing Logical Volume:
There is one last problem I have very less user data in the LV (data), unwantedly there is so much of free space which I want to use that for another LV(some other). I need to reduce the size of the LV (data) from 49 GB to 20 GB. Let we do it by using the following steps.
Run the file system check.
[root@SRV01 ~]# e2fsck -f /dev/smbserver/data
e2fsck 1.39 (29-May-2006)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/smbserver/data: 12/5898240 files (8.3% non-contiguous), 487424/11796480 blocks
Resize the file system to 20 GB using the following command.
[root@SRV01 ~]# resize2fs /dev/smbserver/data 20G
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/smbserver/data to 5242880 (4k) blocks.
The filesystem on /dev/smbserver/data is now 5242880 blocks long.
Then reduce the LV (data) to 20 GB using the following command.
[root@SRV01 ~]# lvreduce -L 20G /dev/smbserver/data
WARNING: Reducing active logical volume to 20.00 GB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce data? [y/n]: y
Reducing logical volume data to 20.00 GB
Logical volume data successfully resized
Check it by using following command.
[root@SRV01 ~]# mount /dev/smbserver/data /smbserver/data/
[root@SRV01 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 965M 467M 449M 51% /
/dev/sda8 5.5G 144M 5.1G 3% /tmp
/dev/sdb5 9.2G 276M 8.5G 4% /opt
/dev/sda7 4.8G 398M 4.1G 9% /home
/dev/sda6 6.2G 1.4G 4.5G 24% /var
/dev/sda5 9.5G 3.3G 5.7G 37% /usr
/dev/sda1 487M 30M 432M 7% /boot
tmpfs 217M 0 217M 0% /dev/shm
/dev/sdb6 11G 155M 9.9G 2% /vm
none 217M 104K 217M 1% /var/lib/xenstored
/dev/hdc 3.7G 3.7G 0 100% /media/CentOS_5.3_Final
/dev/mapper/smbserver-backup
9.9G 1.2G 8.3G 13% /smbserver/backup
/dev/mapper/smbserver-videos
20G 173M 19G 1% /smbserver/videos
/dev/mapper/smbserver-data
20G 1.2G 18G 7% /smbserver/data
The following output will be final after extending and reducing LV.
[root@SRV01 ~]# lvdisplay
— Logical volume —
LV Name /dev/smbserver/data
VG Name smbserver
LV UUID y3MGj1-E0qP-cL1I-MN6R-yzMO-bnRQ-vXef0N
LV Write Access read/write
LV Status available
# open 1
LV Size 20.00 GB
Current LE 5120
Segments 2
Allocation inherit
Read ahead sectors auto
– currently set to 256
Block device 253:0
— Logical volume —
LV Name /dev/smbserver/backup
VG Name smbserver
LV UUID dlk3oC-pB1U-vbMG-BHcB-ZCMg-L0ye-w4MXsc
LV Write Access read/write
LV Status available
# open 1
LV Size 10.00 GB
Current LE 2560
Segments 1
Allocation inherit
Read ahead sectors auto
– currently set to 256
Block device 253:1
— Logical volume —
LV Name /dev/smbserver/videos
VG Name smbserver
LV UUID Gj1Yjy-yWir-rSt6-S2e7-nUvF-XzxF-Y2iNI6
LV Write Access read/write
LV Status available
# open 1
LV Size 20.00 GB
Current LE 5120
Segments 2
Allocation inherit
Read ahead sectors auto
– currently set to 256
Block device 253:2
[root@SRV01 ~]# lvscan
ACTIVE ‘/dev/smbserver/data’ [20.00 GB] inherit
ACTIVE ‘/dev/smbserver/backup’ [10.00 GB] inherit
ACTIVE ‘/dev/smbserver/videos’ [20.00 GB] inherit
Reverting Back:
The following commands will remove all the steps we done above.
[root@SRV01 ~]# umount /dev/smbserver/videos /dev/smbserver/data /dev/smbserver/backup
[root@SRV01 ~]# lvremove /dev/smbserver/videos
[root@SRV01 ~]# lvremove /dev/smbserver/data
[root@SRV01 ~]# lvremove /dev/smbserver/backup
[root@SRV01 ~]# vgremove /dev/smbserver
[root@SRV01 ~]# pvremove /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1
That’s it, the above will give you the basic guide lines to setup LVM on Linux.