[DRBD-user] DRBD and LVM Snapshots on Secondary

Jürgen Scholz juergen at kernkraft400.com
Thu Aug 13 13:34:43 CEST 2009

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


> But I'm trying to achieve the same thing, and I'm wondering if this  
> is at all possible since this was posted back in 2004. I have a 2- 
> node setup in Primary-Secondary mode. LVM2 sits on top of DRBD. Now  
> due to the enormous performance penalty incurred when taking an LVM  
> snapshot of an active LV, I was wondering if it's possible to take  
> the snapshot on the secondary node only for backup purposes, while  
> leaving the primary untouched. I wouldn't care about the performance  
> hit to the secondary, I'm only concerned with the data being  
> "consistent", and not necessarily "clean".
If I understand correctly you want to change the contents of the drbd  
resource on the secondary. You will not be able to do that without  
dual primary and clvm.

You perhaps could use
    Storage <-> LVM <-> DRBD <-> LVM <-> LVs
and do the snapshot for the backup on the lower lvm.

You could disconnect your secondary, promote it to primary, do the  
backup, outdate and reconnect. - But you would lose your consistency  
this way.


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