Actually, how far behind replication is w.r.t. edit logs is different than how out of sync they are, but you get the idea.
On Thu, Mar 3, 2011 at 9:07 AM, Bill Graham <billgra...@gmail.com> wrote: > One more question for the FAQ: > > 6. Is it possible for an admin to tell just how out of sync the two > clusters are? Something like Seconds_Behind_Master in MySQL's SHOW > SLAVE STATUS? > > > On Wed, Mar 2, 2011 at 9:32 PM, Jean-Daniel Cryans <jdcry...@apache.org> > wrote: >> Although, I would add that this feature is still experimental so who knows :) >> >> I think the worst that happened to us was that replication was broken >> (see the jira where if the master loses it's zk session with the slave >> zk ensemble, it requires a HBase restart on the master side) for a few >> days because of maintenance of the link between the two datacenters >> which took more than a minute. When we finally did restart the master >> cluster, it had to process about 2TBs of HLogs... those ICVs can >> really generate a lot of data! >> >> J-D >> >> On Wed, Mar 2, 2011 at 9:25 PM, Jean-Daniel Cryans <jdcry...@apache.org> >> wrote: >>>> 5. If one is adding replication on the *production* Master cluster, what's >>>> the >>>> worst thing that can happen to this Master cluster? Nothing scary other >>>> than >>>> changing configs + interruption during a restart? (which is currently >>>> still bad >>>> because of region assignments?) >>>> >>> >>> The replication code is pretty much encapsulated from the rest of the >>> region server code, it won't mess with your Puts or change your >>> birthday date. >>> >>> With 0.90 the regions are reassigned where they were before, so it's >>> really just the block cache that gets screwed. >>> >>> J-D >>> >> >
