I canceled mmap and indeed memory usage is sane again. So far performance hasn't been great, but I'll wait and see.
I'm also interested in a way to cap mmap so I can take advantage of it but not swap the host to death... On Tue, May 4, 2010 at 9:38 PM, Kyusik Chung <kyu...@discovereads.com>wrote: > This sounds just like the slowness I was asking about in another thread - > after a lot of reads, the machine uses up all available memory on the box > and then starts swapping. > > My understanding was that mmap helps greatly with read and write perf > (until the box starts swapping I guess)...is there any way to use mmap and > cap how much memory it takes up? > > What do people use in production? mmap or no mmap? > > Thanks! > > Kyusik Chung > > On May 4, 2010, at 10:11 AM, Schubert Zhang wrote: > > 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 <shulm...@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.pitt...@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 <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; >> >> ... >> > >> > > >