We are running into the same issue on some of our machines. Still haven't tracked down what is causing it.
________________________________ From: William Oberman [mailto:ober...@civicscience.com] Sent: Thursday, July 07, 2011 7:19 AM To: user@cassandra.apache.org Subject: Re: Cassandra memory problem I think I had (and have) a similar problem: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/OOM-or- what-settings-to-use-on-AWS-large-td6504060.html My memory usage grew slowly until I ran out of mem and the OS killed my process (due to no swap). I'm still on 0.7.4, but I'm rolling out 0.8.1 next week, which I was hoping would fix the problem. I'm using Centos with Sun 1.6.0_24-b07 will On Thu, Jul 7, 2011 at 7:41 AM, Daniel Doubleday <daniel.double...@gmx.net> wrote: Hm - had to digg deeper and it totally looks like a native mem leak to me: We are still growing with res += 100MB a day. Cassandra is > 8G now I checked the cassandra process with pmap -x Here's the human readable (aggregated) output: Format is thingy: RSS in KB Summary: Total SST: 1961616 Anon RSS: 6499640 Total RSS: 8478376 Here's a little more detail: SSTables (data and index files) ****** Attic: 0 PrivateChatNotification: 38108 Schema: 0 PrivateChat: 161048 UserData: 116788 HintsColumnFamily: 0 Rooms: 100548 Tracker: 476 Migrations: 0 ObjectRepository: 793680 BlobStore: 350924 Activities: 400044 LocationInfo: 0 Libraries ****** javajar: 2292 nativelib: 13028 Other ****** 28201: 32 jna979649866618987247.tmp: 92 locale-archive: 1492 [stack]: 132 java: 44 ffi8TsQPY(deleted): 8 And ****** [anon]: 6499640 Maybe the output of pmap is totally misleading but my interpretation is that only 2GB of RSS is attributed to paged in sstables. I have one large anon block which looks like this: Address Kbytes RSS Dirty Mode Mapping 000000073f600000 0 3093248 3093248 rwx-- [ anon ] This is the native heap thats been allocated on startup and mlocked So theres still 3.5GB of anon memory. We haven't deployed https://issues.apache.org/jira/browse/CASSANDRA-2654 yet and this might be part of it but I don't think thats the main problem. As I said mem goes up by 100MB each day pretty linearly. Would be great if anyone could verify this by running pmap or talk my off the roof by explaining that nothing's the way it seems. All this might be heavily OS specific so maybe that's only on Debian? Thanks a lot Daniel On Jul 4, 2011, at 2:42 PM, Jonathan Ellis wrote: mmap'd data will be attributed to res, but the OS can page it out instead of killing the process. On Mon, Jul 4, 2011 at 5:52 AM, Daniel Doubleday <daniel.double...@gmx.net> wrote: Hi all, we have a mem problem with cassandra. res goes up without bounds (well until the os kills the process because we dont have swap) I found a thread that's about the same problem but on OpenJDK: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Very-hi gh-memory-utilization-not-caused-by-mmap-on-sstables-td5840777.html We are on Debian with Sun JDK. Resident mem is 7.4G while heap is restricted to 3G. Anyone else is seeing this with Sun JDK? Cheers, Daniel :/home/dd# java -version java version "1.6.0_24" Java(TM) SE Runtime Environment (build 1.6.0_24-b07) Java HotSpot(TM) 64-Bit Server VM (build 19.1-b02, mixed mode) :/home/dd# ps aux |grep java cass 28201 9.5 46.8 372659544 7707172 ? SLl May24 5656:21 /usr/bin/java -ea -XX:+UseThreadPriorities -XX:ThreadPriorityPolicy=42 -Xms3000M -Xmx3000M -Xmn400M ... PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 28201 cass 20 0 355g 7.4g 1.4g S 8 46.9 5656:25 java -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
