Chris, I'm curious if this happens when hbase.hregion.max.filesize is set to the default 256m. Have you tested it?
Sandy > -----Original Message----- > From: Christopher Tarnas [mailto:[email protected]] On Behalf Of Chris Tarnas > Sent: Friday, January 07, 2011 23:07 > To: [email protected] > Subject: Strange regionserver behavior with GZ compression > > Thanks in advance for any help. I've been quite pleased with Hbase for this > current project and until this problem it has worked quite well. > > Test cluster setup is CDH3b3 on a 7 nodes: > 5 data nodes with 48GB RAM, 8 cores, 4 disks, > 2 masters with 8 cores, 2 disks 24GB RAM for master/zookeeper/namenode > > My hbase.hregion.max.filesize is set to 1GB, ulimit files to 32k and xceivers > to > 4096, hbase heap is at 8GB. > > I'm testing out using GZ compression on two tables, each is currently still > only > one region. My tests runs fine when compression is off so this is definitely > related to compression. When I start loading data (via thrift, many clients) > it > loads great for a while then the region servers slow to crawl. When this > happens the two regionservers that are hosting the tables use ~ 110-160% > CPU and block writes. One regionserver has occasional bursts of activity but > mostly is very repetitive, here is a sample of the log: > > http://pastebin.com/WSc8aZFQ > > The other active regionserver looks to be continuously compacting: > > http://pastebin.com/3ifVKaX2 > > > The master log is quite boring with this being repeated: > > 2011-01-08 00:48:58,419 INFO > org.apache.hadoop.hbase.master.BaseScanner: > RegionManager.rootScanner scanning meta region {server: 10.56.24.8:60020, > regionname: -ROOT-,,0.70236052, startKey: <>} > 2011-01-08 00:48:58,424 INFO > org.apache.hadoop.hbase.master.BaseScanner: > RegionManager.rootScanner scan of 1 row(s) of meta region {server: > 10.56.24.8:60020, regionname: -ROOT-,,0.70236052, startKey: <>} complete > 2011-01-08 00:48:58,444 INFO > org.apache.hadoop.hbase.master.ServerManager: 5 region servers, 0 dead, > average load 1.6 > 2011-01-08 00:49:04,810 INFO > org.apache.hadoop.hbase.master.BaseScanner: > RegionManager.metaScanner scanning meta region {server: > 10.56.24.7:60020, regionname: .META.,,1.1028785192, startKey: <>} > 2011-01-08 00:49:04,820 INFO > org.apache.hadoop.hbase.master.BaseScanner: > RegionManager.metaScanner scan of 6 row(s) of meta region {server: > 10.56.24.7:60020, regionname: .META.,,1.1028785192, startKey: <>} complete > 2011-01-08 00:49:04,820 INFO > org.apache.hadoop.hbase.master.BaseScanner: All 1 .META. region(s) > scanned > > > At this point loading slows to a trickle (requests are 0 in the web ui), I > can see > infrequent bursts of loading but very small amounts. Each table only has one > region (and there are only two other tables, each also with only one region). > > I've compiled and tested the native GZ compression codecs on the nodes > and the nodes have plenty of CPU, IO and memory available and no > swapping. Any suggestions? Please let me know if you need any other info. > > thanks! > -chris
