Online EXT4 on LVM resize

Have such partitions/volumes/mountpoints:

=$ LC_ALL=C df -hP | column -t
Filesystem              Size  Used  Avail  Use%  Mounted  on
/dev/mapper/vg0-rootlv  19G   854M  17G    5%    /
/dev/mapper/vg0-homelv  19G   343M  18G    2%    /home
/dev/mapper/vg0-optlv   19G   192M  18G    2%    /opt
/dev/mapper/vg0-varlv   19G   357M  18G    2%    /var

Question is: how can I grow /home and /var partitions (to 100GB and 400GB respectively)?

Is it safe to do it online with database running on this server?

Solution 1:

First check if you have free space in volume group:

vgs

then resize the volumes:

lvresize -L 400G /dev/mapper/vg0-varlv
lvresize -L 100G /dev/mapper/vg0-homelv

and resize the filesystems residing on them:

resize2fs /dev/mapper/vg0-varlv
resize2fs /dev/mapper/vg0-homelv

I have to note though that resizing a partition from 20GB to 400GB will make your inodes quite sparse. If it is at all possible I strongly recommend creating new volumes with new filesystems and moving data there. You can copy the files during normal operation and then just rsync the changed files to new partition during downtime.