What are you seeing in compaction stats ? You may see some of https://issues.apache.org/jira/browse/CASSANDRA-2280
Cheers ----------------- Aaron Morton Freelance Cassandra Developer @aaronmorton http://www.thelastpickle.com On 21 Jul 2011, at 23:17, Yan Chunlu wrote: > after tried nodetool -h reagon repair key cf, I found that even repair single > CF, it involves rebuild all sstables(using nodetool compactionstats), is that > normal? > > On Thu, Jul 21, 2011 at 7:56 AM, Aaron Morton <aa...@thelastpickle.com> wrote: > If you have never run repair also check the section on repair on this page > http://wiki.apache.org/cassandra/Operations About how frequently it should be > run. > > There is an issue where repair can stream too much data, and this can lead to > excessive disk use. > > My non scientific approach to the never run repair before problem is to > repair a single CF at a time, starting with the small ones that are less > likely to have differences as they will stream the smallest amount of data. > > If you really want to conserve disk IO during the repair consider disabling > the minor compaction by setting the min and max thresholds to 0 via node tool. > > hope that helps. > > > ----------------- > Aaron Morton > Freelance Cassandra Developer > @aaronmorton > http://www.thelastpickle.com > > On 20/07/2011, at 11:46 PM, Yan Chunlu <springri...@gmail.com> wrote: > >> just found this: >> https://issues.apache.org/jira/browse/CASSANDRA-2156 >> >> but seems only available to 0.8 and people submitted a patch for 0.6, I am >> using 0.7.4, do I need to dig into the code and make my own patch? >> >> does add compaction throttle solve the io problem? thanks! >> >> On Wed, Jul 20, 2011 at 4:44 PM, Yan Chunlu <springri...@gmail.com> wrote: >> at the beginning of using cassandra, I have no idea that I should run "node >> repair" frequently, so basically, I have 3 nodes with RF=3 and have not run >> node repair for months, the data size is 20G. >> >> the problem is when I start running node repair now, it eat up all disk io >> and the server load became 20+ and increasing, the worst thing is, the >> entire cluster has slowed down and can not handle request. so I have to stop >> it immediately because it make my web service unavailable. >> >> the server has Intel Xeon-Lynnfield 3470-Quadcore [2.93GHz] and 8G memory, >> with Western Digital WD RE3 WD1002FBYS SATA disk. >> >> I really have no idea what to do now, as currently I have already found some >> data loss, any suggestions would be appreciated. >> >> >> >> -- >> 闫春路 > > > > -- > 闫春路
