Thanks Gregg & Aaron. Missed that setting! On Tuesday, April 2, 2013, aaron morton wrote:
> Set the min and max > compaction thresholds for a given column family > > +1 for setting the max_compaction_threshold (as well as the min) on the a > CF when you are getting behind. It can limit the size of the compactions > and give things a chance to complete in a reasonable time. > > Cheers > > ----------------- > Aaron Morton > Freelance Cassandra Consultant > New Zealand > > @aaronmorton > http://www.thelastpickle.com > > On 2/04/2013, at 3:42 AM, Gregg Ulrich <gulr...@netflix.com<javascript:_e({}, > 'cvml', 'gulr...@netflix.com');>> > wrote: > > You may want to set compaction threshold and not throughput. If you set > the min threshold to something very large (100000), compactions will not > start until cassandra finds this many files to compact (which it should > not). > > In the past I have used this to stop compactions on a node, and then run > an offline major compaction to get though the compaction, then set the min > threshold back. Not everyone likes major compactions though. > > > > setcompactionthreshold <keyspace> <cfname> <minthreshold> <maxthreshold> > - Set the min and max > compaction thresholds for a given column family > > > > On Mon, Apr 1, 2013 at 12:38 PM, William Oberman > <ober...@civicscience.com<javascript:_e({}, 'cvml', > 'ober...@civicscience.com');> > > wrote: > >> I'll skip the prelude, but I worked myself into a bit of a jam. I'm >> recovering now, but I want to double check if I'm thinking about things >> correct. >> >> Basically, I was in a state where a majority of my servers wanted to do >> compactions, and rather large ones. This was impacting my site >> performance. I tried nodetool stop COMPACTION. I tried >> setcompactionthroughput=1. I tried restarting servers, but they'd restart >> the compactions pretty much immediately on boot. >> >> Then I realized that: >> nodetool stop COMPACTION >> only stopped running compactions, and then the compactions would >> re-enqueue themselves rather quickly. >> >> So, right now I have: >> 1.) scripts running on N-1 servers looping on "nodetool stop COMPACTION" >> in a tight loop >> 2.) On the "Nth" server I've disabled gossip/thrift and turned up >> setcompactionthroughput to 999 >> 3.) When the Nth server completes, I pick from the remaining N-1 (well, >> I'm still running the first compaction, which is going to take 12 more >> hours, but that is the plan at least). >> >> Does this make sense? Other than the fact there was probably warning >> signs that would have prevented me from getting into this state in the >> first place? :-) >> >> will >> > > > -- Will Oberman Civic Science, Inc. 6101 Penn Avenue, Fifth Floor Pittsburgh, PA 15206 (M) 412-480-7835 (E) ober...@civicscience.com
