We just started using LVM on our raid array and feel it is slowing down the snapshot reversal operation that we use to test upgrades. We are not very familiar with this whole Raid and LVM thing so maybe it isn't possible.
So right now, we create a snapshot by doing:
- lvcreate -l 100%FREE -n data_snap -s data/data
- then we run our system upgrade package
- lvconvert --merge 'data/data_snap'
It actually takes a long.... long.... long time to revert so the gain in efficiency is marginal right now. I believe this might be cause by a few problems but i'm trying to see how i can fix a few of those using this question:
- We have the snapshot volume on the same physical disk as the original volume
- We have an active software raid supporting all that in the back that RAID1's on 2 devices SDB and SDC that forms MD0
- Our original setup takes 100% of MD0 to create /storage and we have no space to create the snapshot, so i also have to lvreduce my data/data to make some space and restore it to 100%VG once the snapshot is merged back
- We moved /var to this RAID array on our initial setup, so i have to move it out to SDA and spoof bindings from MD0's /storage mount to SDA's /var, so we keep our docker stuff on the RAID to limit the changes to the volumes
So my options seem to be to find a way to suspend replication of SDB to SDC through MD0. But i have no clue how to do this. It will probably save me a LOT of trouble but i can't be sure.
Can anyone enlighten me?