was starved for CPU. I researched this failure and found
an excellent thread talking about GC: http://forums.sun.com/thread.jspa?threadID=698490 that is more detailed than http://wiki.apache.org/hadoop/PerformanceTuning .I will do some tunning and see if it helps following the posted config there.
Jimmy. -------------------------------------------------- From: "Ryan Rawson" <[email protected]> Sent: Friday, July 16, 2010 1:35 PM To: <[email protected]> Subject: Re: YouAreDeadException with hbase
These 2 lines are different GC collections:5517.355: [GC 5517.355: [ParNew (promotion failed): 18113K->18113K(19136K), 0.7700840 secs] 5518.125: [CMS5649.813: [CMS-concurrent-mark: 171.151/310.961 secs] [Times: user=95.87 sys=3.06, real=310.97 secs](concurrent mode failure): 2009649K->572240K(2054592K), 280.2155930 secs] 20233 25K->572240K(2073728K), [CMS Perm : 18029K->17976K(30064K)] icms_dc=100 , 281.0357280 secs] [Times: user=4.55 sys=4.07, real=281.05 secs] It's a little hard to read that, it looks like the CMS concurrent mark took 310 seconds then failed, then we got a 281 second real time pause, but interestingly enough the user and system time is fairly low. How loaded are these machines? You need to be giving enough uncontended CPU time to hbase.On Fri, Jul 16, 2010 at 1:30 PM, Jinsong Hu <[email protected]> wrote:I already implemented all these configs before my test. I checked gc-hbase.log, I see a GC failure which looks very suspecious: 5515.974: [GC 5515.974: [ParNew: 19120K->2112K(19136K), 0.8344240 secs] 2016283K ->2007324K(2069308K) icms_dc=100 , 0.8345620 secs] [Times: user=0.08 sys=0.00, r eal=0.83 secs]5517.355: [GC 5517.355: [ParNew (promotion failed): 18113K->18113K(19136K),0.77 00840 secs]5518.125: [CMS5649.813: [CMS-concurrent-mark: 171.151/310.961 secs] [ Times: user=95.87 sys=3.06, real=310.97 secs] (concurrent mode failure): 2009649K->572240K(2054592K), 280.2155930 secs] 20233 25K->572240K(2073728K), [CMS Perm : 18029K->17976K(30064K)] icms_dc=100 , 281.03 57280 secs] [Times: user=4.55 sys=4.07, real=281.05 secs] 5798.909: [GC [1 CMS-initial-mark: 572240K(2054592K)] 573896K(2092928K), 0.05792 20 secs] [Times: user=0.01 sys=0.00, real=0.08 secs]the concurrent mode failure, and 281.05 seconds of GC time, looks like theculprit for the problem. I just wonder how to resolve this issue. Jimmy. -------------------------------------------------- From: "Ryan Rawson" <[email protected]> Sent: Friday, July 16, 2010 12:57 PM To: <[email protected]> Subject: Re: YouAreDeadException with hbaseSometimes the GC can chain multiple medium pauses into one large pause. I've seen this before where there are 2 long pauses back to back and the result was a 50second+ pause. This article talks a lot about GC performance and tuning, check it out: http://wiki.apache.org/hadoop/PerformanceTuning -ryan On Fri, Jul 16, 2010 at 11:55 AM, Jinsong Hu <[email protected]> wrote:Yes, the root cause seems to be the gap of 4 minutes between2010-07-16 05:49:26,805 and 2010-07-16 05:53:23,476 . but I checked GCgc-hbase.log and don't see 4 minute gap in gc. I just wonder what could cause this large gap. I also wonder if there is a configuration that I can do to avoid this long pause, or get around the problem cause by this long pause. Jimmy -------------------------------------------------- From: "Stack" <[email protected]> Sent: Friday, July 16, 2010 11:44 AM To: <[email protected]> Subject: Re: YouAreDeadException with hbaseYou'll see this if the server reports to the master after the master has ruled it 'dead'. Here is the code that produces the exception: if (!isDead(serverName)) return;String message = "Server " + what + " rejected; currently processing "+ serverName + " as dead server"; LOG.debug(message); throw new YouAreDeadException(message); Servers are on the 'dead' list if zk reports their session has expired. The master moves then to cleanup after the dead server and process its logs. If during this cleanup time the server reports in, master will return the youaredead exception. Usually the RS has lost its zk session but has yet to realize it. St.Ack On Thu, Jul 15, 2010 at 11:52 PM, Jinsong Hu <[email protected]> wrote:Hi, There: I got some YouAreDeadException with hbase. what can cause it ? I do notice between 5:49 to 5:53 , for 4 minutes, there is no log. This doesn't look like GC issue as I checked the GC log, the longest GC is only 9.6 seconds. Jimmy. 2010-07-16 05:49:26,805 DEBUG org.apache.hadoop.hbase.io.hfile.LruBlockCache: Ca che Stats: Sizes: Total=3.355194MB (3518176), Free=405.4198MB (425113472), Max=4 08.775MB (428631648), Counts: Blocks=1, Access=2178914, Hit=1034, Miss=2177880, Evictions=0, Evicted=0, Ratios: Hit Ratio=0.04745483165606856%, Miss Ratio=99.95 254278182983%, Evicted/Run=NaN 2010-07-16 05:53:23,476 DEBUG org.apache.hadoop.hbase.io.hfile.LruBlockCache: Ca che Stats: Sizes: Total=3.355194MB (3518176), Free=405.4198MB (425113472), Max=4 08.775MB (428631648), Counts: Blocks=1, Access=2178915, Hit=1035, Miss=2177880, Evictions=0, Evicted=0, Ratios: Hit Ratio=0.04750070511363447%, Miss Ratio=99.95 250105857849%, Evicted/Run=NaN .... 2010-07-16 05:53:26,171 INFO org.apache.zookeeper.ClientCnxn: Client session tim ed out, have not heard from server in 240540ms for sessionid 0x329c88039b0006c, closing socket connection and attempting reconnect 2010-07-16 05:53:27,333 INFO org.apache.zookeeper.ClientCnxn: Opening socket con nection to server t-zookeeper2.cloud.ppops.net/10.110.24.57:2181 2010-07-16 05:53:27,334 INFO org.apache.zookeeper.ClientCnxn: Socket connection established to t-zookeeper2.cloud.ppops.net/10.110.24.57:2181, initiating sessio n2010-07-16 05:53:27,335 INFO org.apache.zookeeper.ClientCnxn: Unable toreconnect to ZooKeeper service, session 0x329c88039b0006c has expired, closingsocket co nnection 2010-07-16 05:53:27,896 INFO org.apache.zookeeper.ClientCnxn: Client session tim ed out, have not heard from server in 240520ms for sessionid 0x129c87a7f98007a, closing socket connection and attempting reconnect 2010-07-16 05:53:39,090 FATAL org.apache.hadoop.hbase.regionserver.HRegionServer : Aborting region server serverName=m0002028.ppops.net,60020,1279237223465, load =(requests=952, regions=21, usedHeap=575, maxHeap=2043): Unhandled exception org.apache.hadoop.hbase.YouAreDeadException: org.apache.hadoop.hbase.YouAreDeadE xception: Server REPORT rejected; currently processing m0002028.ppops.net,60020, 1279237223465 as dead server at org.apache.hadoop.hbase.master.ServerManager.checkIsDead(ServerManage r.java:217) at org.apache.hadoop.hbase.master.ServerManager.regionServerReport(Serve rManager.java:271) at org.apache.hadoop.hbase.master.HMaster.regionServerReport(HMaster.jav a:684) at sun.reflect.GeneratedMethodAccessor2.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces sorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.hadoop.hbase.ipc.HBaseRPC$Server.call(HBaseRPC.java:576) at org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java: 919)
