[DRBD-user] Start resources after full drbd sync

Pawel Warowny warp at master.pl
Tue Jul 5 12:38:13 CEST 2011

Note: "permalinks" may not be as permanent as we would like,
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Hi

Is there any way to configure cluster (pacemaker), so that some 
resource start only after drbd full synchronisation?

My configuration looks like this:
Two nodes with kvm virtualized guests.

node1:
drbd -> dlm -> some other resources -> libvirtd ->
-> VirtualDomain1, VirtualDomain2, (...)  

node2
drbd -> dlm -> some other resources -> libvirtd ->
-> VirtualDomain5, VirtualDomain6, (...)  

VirtualDomains can move between nodes in case of some node is
unavailable.

What Am I worry about:

- some bad thing happened on node2
- node1 stonith node2, so node2 is rebooted
- VirtualDomains from node2 migrate to node1
- node2 started after reboot and starting cluster resources
- node2: drbd resync and getting primary before full sync.
- after drbd promotion all other resources is starting on node2
- VirtualDomains which migrated after stonith now is going back to node2

and here is the problem, I don't want this migration while drbd is
syncing. It leads to heavily I/O load while drbd is syncing and at the
same time VirutalDomains are migrating. Under heavy I/O load migration
is slow and inefficient .

Even worse, while drbd is syncing and VirtualDomains are migrating
under heavy load some VirtualDomain migration failed and because
of that node2 stonith node1.

In this situation node1 is rebooting and we have inconsistent drbd
resource on node2 so every resource above drbd will fail.
Node1 started after reboot and again stonith node2 because failed
resources on it.

I know that I can configure resource stickiness which will prevent
migration but this auto migration is important feature for me.

Best regards

-- 
Pawel Warowny
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