[DRBD-user] Drbd + LVM snapshots?

Hari Sekhon hpsekhon at googlemail.com
Thu Mar 12 14:34:03 CET 2009

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Has anyone used Drbd with LVM snapshots?

I have lvm on top of drbd so that I can try snapshotting the contents of 
the main storage on the primary node while it has it mounted.

drbd0 - > partition1 (large)
drbd1 -> partition2 (small)

one vg on top of drbd0 and drbd1.

I know about not putting any fs across two devices due to the lack of 
guarantee on consistency, so I restricted the lv to use only the drbd0 
device completely and left the smaller drbd1 device for snapshots.
I made the snapshot successfully (read only) but it seems as though I 
cannot mount the snapshot to read from it.

I guess this is due to some drbd magic locking or something under the 
hood to change the block headers to not work for data safety.

I really want to both replicate (which is working well) and also to take 
snapshots of the main area some how.
Can anyone tell me if what I am trying to do is completely off or if 
this can be done in another way?

-h

-- 
Hari Sekhon
Always open to interesting opportunities
http://www.linkedin.com/in/harisekhon




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