4 Resize Logical Volumes And Their Filesystems
In this chapter we will learn how to resize our logical volume share which has an ext3 filesystem. (I will show how to resize logical volumes with xfs and reiserfs filesystems further down this tutorial.)
First we must unmount it:
umount /var/share
share should not be listed anymore in the
df -h
output:
server1:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 19G 665M 17G 4% /
tmpfs 78M 0 78M 0% /lib/init/rw
udev 10M 88K 10M 1% /dev
tmpfs 78M 0 78M 0% /dev/shm
/dev/sda1 137M 17M 114M 13% /boot
/dev/mapper/fileserver-backup
5.0G 144K 5.0G 1% /var/backup
/dev/mapper/fileserver-media
1.0G 33M 992M 4% /var/media
Now let's enlarge share from 40GB to 50GB:
lvextend -L50G /dev/fileserver/share
server1:~# lvextend -L50G /dev/fileserver/share
Extending logical volume share to 50.00 GB
Logical volume share successfully resized
Until now we have enlarged only share, but not the ext3 filesystem on share. This is what we do now:
e2fsck -f /dev/fileserver/share
server1:~# e2fsck -f /dev/fileserver/share
e2fsck 1.40-WIP (14-Nov-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/fileserver/share: 11/5242880 files (9.1% non-contiguous), 209588/10485760 blocks
Make a note of the total amount of blocks (10485760) because we need it when we shrink share later on.
resize2fs /dev/fileserver/share
server1:~# resize2fs /dev/fileserver/share
resize2fs 1.40-WIP (14-Nov-2006)
Resizing the filesystem on /dev/fileserver/share to 13107200 (4k) blocks.
The filesystem on /dev/fileserver/share is now 13107200 blocks long.
Let's mount share:
mount /dev/fileserver/share /var/share
and in the
df -h
output share should now have 50GB instead of 40:
server1:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 19G 665M 17G 4% /
tmpfs 78M 0 78M 0% /lib/init/rw
udev 10M 88K 10M 1% /dev
tmpfs 78M 0 78M 0% /dev/shm
/dev/sda1 137M 17M 114M 13% /boot
/dev/mapper/fileserver-backup
5.0G 144K 5.0G 1% /var/backup
/dev/mapper/fileserver-media
1.0G 33M 992M 4% /var/media
/dev/mapper/fileserver-share
50G 180M 47G 1% /var/share
Shrinking a logical volume is the other way round: first we must shrink the filesystem before we reduce the logical volume's size. Let's shrink share to 40GB again:
umount /var/share
df -h
server1:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 19G 665M 17G 4% /
tmpfs 78M 0 78M 0% /lib/init/rw
udev 10M 88K 10M 1% /dev
tmpfs 78M 0 78M 0% /dev/shm
/dev/sda1 137M 17M 114M 13% /boot
/dev/mapper/fileserver-backup
5.0G 144K 5.0G 1% /var/backup
/dev/mapper/fileserver-media
1.0G 33M 992M 4% /var/media
e2fsck -f /dev/fileserver/share
server1:~# e2fsck -f /dev/fileserver/share
e2fsck 1.40-WIP (14-Nov-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/fileserver/share: 11/6553600 files (9.1% non-contiguous), 251733/13107200 blocks
When resizing an ext3 filesystem to a certain size (instead of all available space), resize2fs takes the number of blocks as argument (you can as well specify the new size in MB, etc. See
man resize2fs
for more details). From our previous operation we know the 40GB equals 10485760 blocks so we run
resize2fs /dev/fileserver/share 10485760
server1:~# resize2fs /dev/fileserver/share 10485760
resize2fs 1.40-WIP (14-Nov-2006)
Resizing the filesystem on /dev/fileserver/share to 10485760 (4k) blocks.
The filesystem on /dev/fileserver/share is now 10485760 blocks long.
We've shrinked the filesystem, now we must shrink the logical volume, too:
lvreduce -L40G /dev/fileserver/share
server1:~# lvreduce -L40G /dev/fileserver/share
WARNING: Reducing active logical volume to 40.00 GB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce share? [y/n]: <-- y
Reducing logical volume share to 40.00 GB
Logical volume share successfully resized
We can ignore the warning that data might be destroyed because we have shrinked the filesystem before.
Let's mount share again:
mount /dev/fileserver/share /var/share
The output of
df -h
should now look like this:
server1:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 19G 665M 17G 4% /
tmpfs 78M 0 78M 0% /lib/init/rw
udev 10M 88K 10M 1% /dev
tmpfs 78M 0 78M 0% /dev/shm
/dev/sda1 137M 17M 114M 13% /boot
/dev/mapper/fileserver-backup
5.0G 144K 5.0G 1% /var/backup
/dev/mapper/fileserver-media
1.0G 33M 992M 4% /var/media
/dev/mapper/fileserver-share
40G 177M 38G 1% /var/share