Speaking technically, that ain't right. I would: * Check if node .135 is holding a lot of hints. * Take a look on disk and see what is there. * Go through a repair and compact on each node.
Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 2/02/2012, at 9:55 PM, R. Verlangen wrote: > Yes, I already did a repair and cleanup. Currently my ring looks like this: > > Address DC Rack Status State Load Owns > Token > ***.89 datacenter1 rack1 Up Normal 2.44 GB 50.00% 0 > ***.135 datacenter1 rack1 Up Normal 6.99 GB 50.00% > 85070591730234615865843651857942052864 > > It's not really a problem, but I'm still wondering why this happens. > > 2012/2/1 aaron morton <aa...@thelastpickle.com> > Do you mean the load in nodetool ring is not even, despite the tokens been > evenly distributed ? > > I would assume this is not the case given the difference, but it may be hints > given you have just done an upgrade. Check the system using nodetool cfstats > to see. They will eventually be delivered and deleted. > > More likely you will want to: > 1) nodetool repair to make sure all data is distributed then > 2) nodetool cleanup if you have changed the tokens at any point finally > > Cheers > > ----------------- > Aaron Morton > Freelance Developer > @aaronmorton > http://www.thelastpickle.com > > On 31/01/2012, at 11:56 PM, R. Verlangen wrote: > >> After running 3 days on Cassandra 1.0.7 it seems the problem has been >> solved. One weird thing remains, on our 2 nodes (both 50% of the ring), the >> first's usage is just over 25% of the second. >> >> Anyone got an explanation for that? >> >> 2012/1/29 aaron morton <aa...@thelastpickle.com> >> Yes but… >> >> For every upgrade read the NEWS.TXT it will go through the upgrade procedure >> in detail. If you want to feel extra smart scan through the CHANGES.txt to >> get an idea of whats going on. >> >> Cheers >> >> ----------------- >> Aaron Morton >> Freelance Developer >> @aaronmorton >> http://www.thelastpickle.com >> >> On 29/01/2012, at 4:14 AM, Maxim Potekhin wrote: >> >>> Sorry if this has been covered, I was concentrating solely on 0.8x -- >>> can I just d/l 1.0.x and continue using same data on same cluster? >>> >>> Maxim >>> >>> >>> On 1/28/2012 7:53 AM, R. Verlangen wrote: >>>> >>>> Ok, seems that it's clear what I should do next ;-) >>>> >>>> 2012/1/28 aaron morton <aa...@thelastpickle.com> >>>> There are no blockers to upgrading to 1.0.X. >>>> >>>> A >>>> ----------------- >>>> Aaron Morton >>>> Freelance Developer >>>> @aaronmorton >>>> http://www.thelastpickle.com >>>> >>>> On 28/01/2012, at 7:48 AM, R. Verlangen wrote: >>>> >>>>> Ok. Seems that an upgrade might fix these problems. Is Cassandra 1.x.x >>>>> stable enough to upgrade for, or should we wait for a couple of weeks? >>>>> >>>>> 2012/1/27 Edward Capriolo <edlinuxg...@gmail.com> >>>>> I would not say that issuing restart after x days is a good idea. You are >>>>> mostly developing a superstition. You should find the source of the >>>>> problem. It could be jmx or thrift clients not closing connections. We >>>>> don't restart nodes on a regiment they work fine. >>>>> >>>>> >>>>> On Thursday, January 26, 2012, Mike Panchenko <m...@mihasya.com> wrote: >>>>> > There are two relevant bugs (that I know of), both resolved in somewhat >>>>> > recent versions, which make somewhat regular restarts beneficial >>>>> > https://issues.apache.org/jira/browse/CASSANDRA-2868 (memory leak in >>>>> > GCInspector, fixed in 0.7.9/0.8.5) >>>>> > https://issues.apache.org/jira/browse/CASSANDRA-2252 (heap >>>>> > fragmentation due to the way memtables used to be allocated, refactored >>>>> > in 1.0.0) >>>>> > Restarting daily is probably too frequent for either one of those >>>>> > problems. We usually notice degraded performance in our ancient cluster >>>>> > after ~2 weeks w/o a restart. >>>>> > As Aaron mentioned, if you have plenty of disk space, there's no reason >>>>> > to worry about "cruft" sstables. The size of your active set is what >>>>> > matters, and you can determine if that's getting too big by watching >>>>> > for iowait (due to reads from the data partition) and/or paging >>>>> > activity of the java process. When you hit that problem, the solution >>>>> > is to 1. try to tune your caches and 2. add more nodes to spread the >>>>> > load. I'll reiterate - looking at raw disk space usage should not be >>>>> > your guide for that. >>>>> > "Forcing" a gc generally works, but should not be relied upon (note >>>>> > "suggest" in >>>>> > http://docs.oracle.com/javase/6/docs/api/java/lang/System.html#gc()). >>>>> > It's great news that 1.0 uses a better mechanism for releasing unused >>>>> > sstables. >>>>> > nodetool compact triggers a "major" compaction and is no longer a >>>>> > recommended by datastax (details here >>>>> > http://www.datastax.com/docs/1.0/operations/tuning#tuning-compaction >>>>> > bottom of the page). >>>>> > Hope this helps. >>>>> > Mike. >>>>> > On Wed, Jan 25, 2012 at 5:14 PM, aaron morton <aa...@thelastpickle.com> >>>>> > wrote: >>>>> > >>>>> > That disk usage pattern is to be expected in pre 1.0 versions. Disk >>>>> > usage is far less interesting than disk free space, if it's using 60 GB >>>>> > and there is 200GB thats ok. If it's using 60Gb and there is 6MB free >>>>> > thats a problem. >>>>> > In pre 1.0 the compacted files are deleted on disk by waiting for the >>>>> > JVM do decide to GC all remaining references. If there is not enough >>>>> > space (to store the total size of the files it is about to write or >>>>> > compact) on disk GC is forced and the files are deleted. Otherwise they >>>>> > will get deleted at some point in the future. >>>>> > In 1.0 files are reference counted and space is freed much sooner. >>>>> > With regard to regular maintenance, node tool cleanup remvos data from >>>>> > a node that it is no longer a replica for. This is only of use when you >>>>> > have done a token move. >>>>> > I would not recommend a daily restart of the cassandra process. You >>>>> > will lose all the run time optimizations the JVM has made (i think the >>>>> > mapped files pages will stay resident). As well as adding additional >>>>> > entropy to the system which must be repaired via HH, RR or nodetool >>>>> > repair. >>>>> > If you want to see compacted files purged faster the best approach >>>>> > would be to upgrade to 1.0. >>>>> > Hope that helps. >>>>> > ----------------- >>>>> > Aaron Morton >>>>> > Freelance Developer >>>>> > @aaronmorton >>>>> > http://www.thelastpickle.com >>>>> > On 26/01/2012, at 9:51 AM, R. Verlangen wrote: >>>>> > >>>>> > In his message he explains that it's for " Forcing a GC ". GC stands >>>>> > for garbage collection. For some more background see: >>>>> > http://en.wikipedia.org/wiki/Garbage_collection_(computer_science) >>>>> > Cheers! >>>>> > >>>>> > 2012/1/25 <mike...@thomsonreuters.com> >>>>> > >>>>> > Karl, >>>>> > >>>>> > Can you give a little more details on these 2 lines, what do they do? >>>>> > >>>>> > java -jar cmdline-jmxclient-0.10.3.jar - localhost:8080 >>>>> > java.lang:type=Memory gc >>>>> > >>>>> > Thank you, >>>>> > Mike >>>>> > >>>>> > -----Original Message----- >>>>> > From: Karl Hiramoto [mailto:k...@hiramoto.org] >>>>> > Sent: Wednesday, January 25, 2012 12:26 PM >>>>> > To: user@cassandra.apache.org >>>>> > Subject: Re: Restart cassandra every X days? >>>>> > >>>>> > >>>>> > On 01/25/12 19:18, R. Verlangen wrote: >>>>> >> Ok thank you for your feedback. I'll add these tasks to our daily >>>>> >> cassandra maintenance cronjob. Hopefully this will keep things under >>>>> >> controll. >>>>> > >>>>> > I forgot to mention that we found that Forcing a GC also cleans up some >>>>> > space. >>>>> > >>>>> > >>>>> > in a cronjob you can do this with >>>>> > http://crawler.archive.org/cmdline-jmxclient/ >>>>> > >>>>> > >>>>> > my cron >>>>> >>>> >>>> >>> >> >> > >
