not quite sure about the overall problem, but bitcask does do compaction if your "casks" reach a certain threshold of dead bytes. this is all configurable and would only be triggered if your updates or deletes pushed your dead bytes over that threshold.
-alexander On Feb 9, 2011, at 12:12 PM, Anthony Molinaro wrote: > Hi, > > Any thoughts on this? I added a timeout to my client so its not impacted > (other than missing some data, but that's okay). However, I still see large > spikes in the node_(get|put)_fsm_time_100 stats (normal operation seems to be > about 1200, and I see spikes up to 200000). > > One thing I thought of is upping the number of async threads. I did > increase the number of partitions to 1024 and with only 4 nodes in the > ring I could be hitting some sort of locking at the bitcask layer. > > Are there any maintenance tasks that happen with bitcask that could > cause lag? For instance in our frequency server which uses riak_core > with a linked in driver for a backend, we have to grow the file every > so often which lead to these sort of spikes, so maybe bitcask has some > thing similar? > > Thanks, > > -Anthony > > On Tue, Feb 08, 2011 at 12:09:34PM -0800, Anthony Molinaro wrote: >> Hi, >> >> I have a 4 node cluster using riak_kv_multi_backend with one backend >> configured to use riak_kv_bitcask_backend. I'm using the multi backend >> because eventually I want to also run a cache backend. I'm sampling >> the statistics once per minute and viewing them in rrd and noticed >> something odd. The node_(get|put)_fsm_time_100 sometimes spike to >> 60 seconds while 99.99% of the time it's less than 2 milliseconds. >> >> I'm going to work around by lowering the timeouts in riak-erlang-client >> but this seems like it could continue to be a problem if the get/put >> fsms continue to run even if the client times out. >> >> Anyway, just curious if others have experienced this sort of long tail >> spikiness. >> >> -Anthony >> >> -- >> ------------------------------------------------------------------------ >> Anthony Molinaro <antho...@alumni.caltech.edu> >> >> _______________________________________________ >> riak-users mailing list >> riak-users@lists.basho.com >> http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com > > -- > ------------------------------------------------------------------------ > Anthony Molinaro <antho...@alumni.caltech.edu> > > _______________________________________________ > riak-users mailing list > riak-users@lists.basho.com > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com _______________________________________________ riak-users mailing list riak-users@lists.basho.com http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
