Can I lvreduce after lvextend without losing the ext4 partition inside it?
- by DrSAR
In a botched attempt to move my root partition from one disk to another I have done the following:
added new disk
partitioned it with parted (part #3 is now almost totally filling the disk)
initialized a physical volume
$ pvcreate /dev/sdb3
Physical volume "/dev/sdb3" successfully created
extended the volume group to include this new physical disk
$ vgextend myvg /dev/sdb3
Volume group "myvg" successfully extended
extended the logical volume (I think this is where I ballsed it up: I think I should have pvmove'ed stuff to the new pv in that group - can someone confirm?)
$ lvextend /dev/mapper/myvg-root /dev/sdb3
I would now like to undo the lvextend and then proceed with the original plan of moving the content of the old physical volume over to the new physical volume. Can I reduce the logical volume (I have not yet touched the ext4 partition that sits in /dev/mapper/myvg-root with something like resizefs) without fear of damaging the ext4 filesystem? If so, how do I tell it to reduce by exactly the right amount?
$ lvreduce --by-exactly-the-amount-occupied-by-PV /ev/sdb3 /dev/mapper/myvg-root
