[DRBD-user] Re: primary/primary questions

Doug "superdug" Smith superdug at gmail.com
Wed Apr 30 22:21:31 CEST 2008

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


>

On the topic of Primary/Primary when using GFS.  When one node falls  
out because of a split brain issue.  What is the proper way to  
reconcile the differences between the two nodes without causing an  
issue with GFS, DLM, and CLVMD.

More specific issues, CLVMD seems to panic when the disk underneath it  
changes (IE: When a side discards its changes and becomes the Sync  
Target).  When CLVMD is running, the CMAN services cannot be stopped.

The only way I have been able to successfully recover after split  
brain is to turn the CLVMD service off, then turn the CMAN services  
off (which turns off DLM which has locking happening) and then proceed  
with the Sync.

I would like to be able to correct Split brain by only taking offline  
the services I need to.  From the documentation I've read on CLVMD  
whenever the disk changes underneath it, it has to be restarted.

An ideal situation would be to take the Sync Target node out of the  
cluster and turn off GFS.  Then do the resync, and bring CMAN back  
online, do a manual fence from the Sync Source node, and then bring  
CLVMD back online.

Thus bringing me back to how to resolve split brain on a GFS disk on  
top of a Primary/Primary DRBD setup correctly.

Thanks,

Doug



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