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From Schubert Zhang <zson...@gmail.com>
Subject Re: performance tuning - where does the slowness come from?
Date Tue, 04 May 2010 17:11:57 GMT
1. When initially startup your nodes, please plan your InitialToken of each
node evenly.
2. <DiskAccessMode>standard</DiskAccessMode>

On Tue, May 4, 2010 at 9:09 PM, Boris Shulman <shulmanb@gmail.com> wrote:

> I think that the extra (more than 4GB) memory usage comes from the
> mmaped io, that is why it happens only for reads.
>
> On Tue, May 4, 2010 at 2:02 PM, Jordan Pittier <jordan.pittier@gmail.com>
> wrote:
> > I'm facing the same issue with swap. It only occurs when I perform read
> > operations (write are very fast :)). So I can't help you with the memory
> > probleme.
> >
> > But to balance the load evenly between nodes in cluster just manually fix
> > their token.(the "formula" is i * 2^127 / nb_nodes).
> >
> > Jordzn
> >
> > On Tue, May 4, 2010 at 8:20 AM, Ran Tavory <rantav@gmail.com> wrote:
> >>
> >> I'm looking into performance issues on a 0.6.1 cluster. I see two
> >> symptoms:
> >> 1. Reads and writes are slow
> >> 2. One of the hosts is doing a lot of GC.
> >> 1 is slow in the sense that in normal state the cluster used to make
> >> around 3-5k read and writes per second (6-10k operations per second),
> but
> >> how it's in the order of 200-400 ops per second, sometimes even less.
> >> 2 looks like this:
> >> $ tail -f /outbrain/cassandra/log/system.log
> >>  INFO [GC inspection] 2010-05-04 00:42:18,636 GCInspector.java (line
> 110)
> >> GC for ParNew: 672 ms, 166482384 reclaimed leaving 2872087208 used; max
> is
> >> 4432068608
> >>  INFO [GC inspection] 2010-05-04 00:42:28,638 GCInspector.java (line
> 110)
> >> GC for ParNew: 498 ms, 166493352 reclaimed leaving 2836049448 used; max
> is
> >> 4432068608
> >>  INFO [GC inspection] 2010-05-04 00:42:38,640 GCInspector.java (line
> 110)
> >> GC for ParNew: 327 ms, 166091528 reclaimed leaving 2796888424 used; max
> is
> >> 4432068608
> >> ... and it goes on and on for hours, no stopping...
> >> The cluster is made of 6 hosts, 3 in one DC and 3 in another.
> >> Each host has 8G RAM.
> >> -Xmx=4G
> >> For some reason, the load isn't distributed evenly b/w the hosts,
> although
> >> I'm not sure this is the cause for slowness
> >> $ nodetool -h localhost -p 9004 ring
> >> Address       Status     Load          Range
> >>        Ring
> >>
> >> 144413773383729447702215082383444206680
> >> 192.168.252.99Up         15.94 GB
> >>  66002764663998929243644931915471302076     |<--|
> >> 192.168.254.57Up         19.84 GB
> >>  81288739225600737067856268063987022738     |   ^
> >> 192.168.254.58Up         973.78 MB
> >> 86999744104066390588161689990810839743     v   |
> >> 192.168.252.62Up         5.18 GB
> >> 88308919879653155454332084719458267849     |   ^
> >> 192.168.254.59Up         10.57 GB
> >>  142482163220375328195837946953175033937    v   |
> >> 192.168.252.61Up         11.36 GB
> >>  144413773383729447702215082383444206680    |-->|
> >> The slow host is 192.168.252.61 and it isn't the most loaded one.
> >> The host is waiting a lot on IO and the load average is usually 6-7
> >> $ w
> >>  00:42:56 up 11 days, 13:22,  1 user,  load average: 6.21, 5.52, 3.93
> >> $ vmstat 5
> >> procs -----------memory---------- ---swap-- -----io---- --system--
> >> -----cpu------
> >>  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy
> id
> >> wa st
> >>  0  8 2147844  45744   1816 4457384    6    5    66    32    5    2  1
>  1
> >> 96  2  0
> >>  0  8 2147164  49020   1808 4451596  385    0  2345    58 3372 9957  2
>  2
> >> 78 18  0
> >>  0  3 2146432  45704   1812 4453956  342    0  2274   108 3937 10732  2
>  2
> >> 78 19  0
> >>  0  1 2146252  44696   1804 4453436  345  164  1939   294 3647 7833  2
>  2
> >> 78 18  0
> >>  0  1 2145960  46924   1744 4451260  158    0  2423   122 4354 14597  2
>  2
> >> 77 18  0
> >>  7  1 2138344  44676    952 4504148 1722  403  1722   406 1388  439 87
>  0
> >> 10  2  0
> >>  7  2 2137248  45652    956 4499436 1384  655  1384   658 1356  392 87
>  0
> >> 10  3  0
> >>  7  1 2135976  46764    956 4495020 1366  718  1366   718 1395  380 87
>  0
> >>  9  4  0
> >>  0  8 2134484  46964    956 4489420 1673  555  1814   586 1601 215590 14
> >>  2 68 16  0
> >>  0  1 2135388  47444    972 4488516  785  833  2390   995 3812 8305  2
>  2
> >> 77 20  0
> >>  0 10 2135164  45928    980 4488796  788  543  2275   626 36
> >> So, the host is swapping like crazy...
> >> top shows that it's using a lot of memory. As noted before -Xmx=4G and
> >> nothing else seems to be using a lot of memory on the host except for
> the
> >> cassandra process, however, of the 8G ram on the host, 92% is used by
> >> cassandra. How's that?
> >> Top shows there's 3.9g Shared and 7.2g Resident and 15.9g Virtual. Why
> >> does it have 15g virtual? And why 7.2 RES? This can explain the slowness
> in
> >> swapping.
> >> $ top
> >>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> >>
> >>
> >> 20281 cassandr  25   0 15.9g 7.2g 3.9g S 33.3 92.6 175:30.27 java
> >> So, can the total memory be controlled?
> >> Or perhaps I'm looking in the wrong direction...
> >> I've looked at all the cassandra JMX counts and nothing seemed
> suspicious
> >> so far. By suspicious i mean a large number of pending tasks - there
> were
> >> always very small numbers in each pool.
> >> About read and write latencies, I'm not sure what the normal state is,
> but
> >> here's an example of what I see on the problematic host:
> >> #mbean = org.apache.cassandra.service:type=StorageProxy:
> >> RecentReadLatencyMicros = 30105.888180684495;
> >> TotalReadLatencyMicros = 78543052801;
> >> TotalWriteLatencyMicros = 4213118609;
> >> RecentWriteLatencyMicros = 1444.4809201925639;
> >> ReadOperations = 4779553;
> >> RangeOperations = 0;
> >> TotalRangeLatencyMicros = 0;
> >> RecentRangeLatencyMicros = NaN;
> >> WriteOperations = 4740093;
> >> And the only pool that I do see some pending tasks is the
> ROW-READ-STAGE,
> >> but it doesn't look like much, usually around 6-8:
> >> #mbean = org.apache.cassandra.concurrent:type=ROW-READ-STAGE:
> >> ActiveCount = 8;
> >> PendingTasks = 8;
> >> CompletedTasks = 5427955;
> >> Any help finding the solution is appreciated, thanks...
> >> Below are a few more JMXes I collected from the system that may be
> >> interesting.
> >> #mbean = java.lang:type=Memory:
> >> Verbose = false;
> >> HeapMemoryUsage = {
> >>   committed = 3767279616;
> >>   init = 134217728;
> >>   max = 4293656576;
> >>   used = 1237105080;
> >>  };
> >> NonHeapMemoryUsage = {
> >>   committed = 35061760;
> >>   init = 24313856;
> >>   max = 138412032;
> >>   used = 23151320;
> >>  };
> >> ObjectPendingFinalizationCount = 0;
> >> #mbean = java.lang:name=ParNew,type=GarbageCollector:
> >> LastGcInfo = {
> >>   GcThreadCount = 11;
> >>   duration = 136;
> >>   endTime = 42219272;
> >>   id = 11719;
> >>   memoryUsageAfterGc = {
> >>     ( CMS Perm Gen ) = {
> >>       key = CMS Perm Gen;
> >>       value = {
> >>         committed = 29229056;
> >>         init = 21757952;
> >>         max = 88080384;
> >>         used = 17648848;
> >>        };
> >>      };
> >>     ( Code Cache ) = {
> >>       key = Code Cache;
> >>       value = {
> >>         committed = 5832704;
> >>         init = 2555904;
> >>         max = 50331648;
> >>         used = 5563520;
> >>        };
> >>      };
> >>     ( CMS Old Gen ) = {
> >>       key = CMS Old Gen;
> >>       value = {
> >>         committed = 3594133504;
> >>         init = 112459776;
> >>         max = 4120510464;
> >>         used = 964565720;
> >>        };
> >>      };
> >>     ( Par Eden Space ) = {
> >>       key = Par Eden Space;
> >>       value = {
> >>         committed = 171835392;
> >>         init = 21495808;
> >>         max = 171835392;
> >>         used = 0;
> >>        };
> >>      };
> >>     ( Par Survivor Space ) = {
> >>       key = Par Survivor Space;
> >>       value = {
> >>         committed = 1310720;
> >>         init = 131072;
> >>         max = 1310720;
> >>         used = 0;
> >>        };
> >>      };
> >>    };
> >>   memoryUsageBeforeGc = {
> >>     ( CMS Perm Gen ) = {
> >>       key = CMS Perm Gen;
> >>       value = {
> >>         committed = 29229056;
> >>         init = 21757952;
> >>         max = 88080384;
> >>         used = 17648848;
> >>        };
> >>      };
> >>     ( Code Cache ) = {
> >>       key = Code Cache;
> >>       value = {
> >>         committed = 5832704;
> >>         init = 2555904;
> >>         max = 50331648;
> >>         used = 5563520;
> >>        };
> >>      };
> >>     ( CMS Old Gen ) = {
> >>       key = CMS Old Gen;
> >>       value = {
> >>         committed = 3594133504;
> >>         init = 112459776;
> >>         max = 4120510464;
> >>         used = 959221872;
> >>        };
> >>      };
> >>     ( Par Eden Space ) = {
> >>       key = Par Eden Space;
> >>       value = {
> >>         committed = 171835392;
> >>         init = 21495808;
> >>         max = 171835392;
> >>         used = 171835392;
> >>        };
> >>      };
> >>     ( Par Survivor Space ) = {
> >>       key = Par Survivor Space;
> >>       value = {
> >>         committed = 1310720;
> >>         init = 131072;
> >>         max = 1310720;
> >>         used = 0;
> >>        };
> >>      };
> >>    };
> >>   startTime = 42219136;
> >>  };
> >> CollectionCount = 11720;
> >> CollectionTime = 4561730;
> >> Name = ParNew;
> >> Valid = true;
> >> MemoryPoolNames = [ Par Eden Space, Par Survivor Space ];
> >> #mbean = java.lang:type=OperatingSystem:
> >> MaxFileDescriptorCount = 63536;
> >> OpenFileDescriptorCount = 75;
> >> CommittedVirtualMemorySize = 17787711488;
> >> FreePhysicalMemorySize = 45522944;
> >> FreeSwapSpaceSize = 2123968512;
> >> ProcessCpuTime = 12251460000000;
> >> TotalPhysicalMemorySize = 8364417024;
> >> TotalSwapSpaceSize = 4294959104;
> >> Name = Linux;
> >> AvailableProcessors = 8;
> >> Arch = amd64;
> >> SystemLoadAverage = 4.36;
> >> Version = 2.6.18-164.15.1.el5;
> >> #mbean = java.lang:type=Runtime:
> >> Name = 20281@ob1061.nydc1.outbrain.com;
> >>
> >> ClassPath =
> >>
> /outbrain/cassandra/apache-cassandra-0.6.1/bin/../conf:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../build/classes:/outbrain/cassandra/apache-cassandra-0.6.1/bin/..
> >>
> >>
> /lib/antlr-3.1.3.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/apache-cassandra-0.6.1.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/avro-1.2.0-dev.jar:/outb
> >>
> >>
> rain/cassandra/apache-cassandra-0.6.1/bin/../lib/clhm-production.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/commons-cli-1.1.jar:/outbrain/cassandra/apache-cassandra-
> >>
> >>
> 0.6.1/bin/../lib/commons-codec-1.2.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/commons-collections-3.2.1.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/com
> >>
> >>
> mons-lang-2.4.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/google-collections-1.0.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/hadoop-core-0.20.1.jar:/out
> >>
> >>
> brain/cassandra/apache-cassandra-0.6.1/bin/../lib/high-scale-lib.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/ivy-2.1.0.jar:/outbrain/cassandra/apache-cassandra-0.6.1/
> >>
> >>
> bin/../lib/jackson-core-asl-1.4.0.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/jackson-mapper-asl-1.4.0.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/jline
> >>
> >>
> -0.9.94.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/json-simple-1.1.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/libthrift-r917130.jar:/outbrain/cassandr
> >>
> >>
> a/apache-cassandra-0.6.1/bin/../lib/log4j-1.2.14.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/slf4j-api-1.5.8.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib
> >> /slf4j-log4j12-1.5.8.jar;
> >>
> >> BootClassPath =
> >>
> /usr/java/jdk1.6.0_17/jre/lib/alt-rt.jar:/usr/java/jdk1.6.0_17/jre/lib/resources.jar:/usr/java/jdk1.6.0_17/jre/lib/rt.jar:/usr/java/jdk1.6.0_17/jre/lib/sunrsasign.j
> >>
> >>
> ar:/usr/java/jdk1.6.0_17/jre/lib/jsse.jar:/usr/java/jdk1.6.0_17/jre/lib/jce.jar:/usr/java/jdk1.6.0_17/jre/lib/charsets.jar:/usr/java/jdk1.6.0_17/jre/classes;
> >>
> >> LibraryPath =
> >>
> /usr/java/jdk1.6.0_17/jre/lib/amd64/server:/usr/java/jdk1.6.0_17/jre/lib/amd64:/usr/java/jdk1.6.0_17/jre/../lib/amd64:/usr/java/packages/lib/amd64:/lib:/usr/lib;
> >>
> >> VmName = Java HotSpot(TM) 64-Bit Server VM;
> >>
> >> VmVendor = Sun Microsystems Inc.;
> >>
> >> VmVersion = 14.3-b01;
> >>
> >> BootClassPathSupported = true;
> >>
> >> InputArguments = [ -ea, -Xms128M, -Xmx4G, -XX:TargetSurvivorRatio=90,
> >> -XX:+AggressiveOpts, -XX:+UseParNewGC, -XX:+UseConcMarkSweepGC,
> >> -XX:+CMSParallelRemarkEnabled, -XX:+HeapDumpOnOutOfMemoryError,
> >> -XX:SurvivorRatio=128, -XX:MaxTenuringThreshold=0,
> >> -Dcom.sun.management.jmxremote.port=9004,
> >> -Dcom.sun.management.jmxremote.ssl=false,
> >> -Dcom.sun.management.jmxremote.authenticate=false,
> >> -Dstorage-config=/outbrain/cassandra/apache-cassandra-0.6.1/bin/../conf,
> >> -Dcassandra-pidfile=/var/run/cassandra.pid ];
> >>
> >> ManagementSpecVersion = 1.2;
> >>
> >> SpecName = Java Virtual Machine Specification;
> >>
> >> SpecVendor = Sun Microsystems Inc.;
> >>
> >> SpecVersion = 1.0;
> >>
> >> StartTime = 1272911001415;
> >> ...
> >
>

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