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 <ran...@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 = 20...@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;
> ...
>
