I'd be curious to see what happens if you split the table into 1 region per CPU core, so 24 cores * 11 servers = 264 regions. Each region has 1 memstore which is a ConcurrentSkipListMap, and you're currently hitting each CSLM with 8 cores which might be too contentious. Normally in production you would want multiple memstores per CPU core.
On Mon, Mar 19, 2012 at 5:31 AM, Juhani Connolly <juha...@gmail.com> wrote: > Actually we did try running off two machines both running our own > tests in parallel. Unfortunately the results were a split that results > in the same total throughput. We also did the same thing with iperf > running from each machine to another machine, indicating 800Mb > additional throughput between each pair of machines. > However we didn't try these tests very thoroughly so I will revisit > them as soon as I get back to the office, thanks. > > On Mon, Mar 19, 2012 at 9:21 PM, Christian Schäfer <syrious3...@yahoo.de> > wrote: > > referring to my experiences I expect the client to be the bottleneck, > too. > > > > So try to increase the count of client-machines (not client threads) > each with its own unshared network interface. > > > > In my case I could double write throughput by doubling client machine > count with a much smaller system than yours (5 machines, 4gigs RAM each). > > > > Good Luck > > Chris > > > > > > > > ________________________________ > > Von: Juhani Connolly <juha...@gmail.com> > > An: user@hbase.apache.org > > Gesendet: 13:02 Montag, 19.März 2012 > > Betreff: Re: 0.92 and Read/writes not scaling > > > > I was concerned that may be the case too, which is why we ran the ycsb > > tests in addition to our application specific and general performance > > tests. checking profiles of the execution just showed the vast majority > of > > time spent waiting for responses. these were all run with 400 > > threads(though we tried more/less just in case) > > 2012/03/19 20:57 "Mingjian Deng" <koven2...@gmail.com>: > > > >> @Juhani: > >> How many clients did you test? Maybe the bottleneck was client? > >> > >> 2012/3/19 Ramkrishna.S.Vasudevan <ramkrishna.vasude...@huawei.com> > >> > >> > Hi Juhani > >> > > >> > Can you tell more on how the regions are balanced? > >> > Are you overloading only specific region server alone? > >> > > >> > Regards > >> > Ram > >> > > >> > > -----Original Message----- > >> > > From: Juhani Connolly [mailto:juha...@gmail.com] > >> > > Sent: Monday, March 19, 2012 4:11 PM > >> > > To: user@hbase.apache.org > >> > > Subject: 0.92 and Read/writes not scaling > >> > > > >> > > Hi, > >> > > > >> > > We're running into a brick wall where our throughput numbers will > not > >> > > scale as we increase server counts both using custom inhouse tests > and > >> > > ycsb. > >> > > > >> > > We're using hbase 0.92 on hadoop 0.20.2(we also experience the same > >> > > issues using 0.90 before switching our testing to this version). > >> > > > >> > > Our cluster consists of: > >> > > - Namenode and hmaster on separate servers, 24 core, 64gb > >> > > - up to 11 datanode/regionservers. 24 core, 64gb, 4 * 1tb disks(hope > >> > > to get this changed) > >> > > > >> > > We have adjusted our gc settings, and mslabs: > >> > > > >> > > <property> > >> > > <name>hbase.hregion.memstore.mslab.enabled</name> > >> > > <value>true</value> > >> > > </property> > >> > > > >> > > <property> > >> > > <name>hbase.hregion.memstore.mslab.chunksize</name> > >> > > <value>2097152</value> > >> > > </property> > >> > > > >> > > <property> > >> > > <name>hbase.hregion.memstore.mslab.max.allocation</name> > >> > > <value>1024768</value> > >> > > </property> > >> > > > >> > > hdfs xceivers is set to 8192 > >> > > > >> > > We've experimented with a variety of handler counts for namenode, > >> > > datanodes and regionservers with no changes in throughput. > >> > > > >> > > For testing with ycsb, we do the following each time(with nothing > else > >> > > using the cluster): > >> > > - truncate test table > >> > > - add a small amount of data, then split the table into 32 regions > and > >> > > call balancer from the shell. > >> > > - load 10m rows > >> > > - do a 1:2:7 insert:update:read test with 10million rows (64k/sec) > >> > > - do a 5:5 insert:update test with 10 million rows (23k/sec) > >> > > - do a pure read test with 10 million rows (75k/sec) > >> > > > >> > > We have observed ganglia, iostat -d -x, iptraf, top, dstat and a > >> > > variety of other diagnostic tools and network/io/cpu/memory as > >> > > bottlenecks seem highly unlikely as none of them are ever seriously > >> > > taxed. This leave me to assume this is some kind of locking issue? > >> > > Delaying WAL flushes gives a small throughput bump but it doesn't > >> > > scale. > >> > > > >> > > There also doesn't seem to be many figures around to compare ours > to. > >> > > We can get our throughput numbers higher with tricks like not > writing > >> > > the WAL or delaying flushes, batching requests, but nothing seems to > >> > > scale with additional slaves. > >> > > Could anyone provide guidance as to what may be preventing > throughput > >> > > figures from scaling as we increase our slave count? > >> > > >> > > >> >
