Propagating file locks across network

tridge at tridge at
Thu Jul 12 01:37:54 GMT 2007


 > What happens to CTDB if the cluster is split into two (or more) subnets?  Will 
 > each fragment continue to operate normally?   That's the goal I'm after.

The way ctdb detects a 'split network' is by using the
CTDB_RECOVERY_LOCK file (see /etc/sysconfig/ctdb). A 'recovery master'
node will only be elected if it can get that lock.

So if you split, and two nodes got that lock, then ctdb would allow
you to continue. But when the two networks came back together again
ctdb may well detect an inconsistency, and might report a fatal error.

So you'd need to modify ctdb to handle situations where you don't mind
inconsistent results. We could have that as a non-default config
option if you do a good patch for it.

Cheers, Tridge

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