> 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> 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> > 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 >
