Daniel Tate wrote:
Unfortunately it did not. It continued to grow and grow until oom killed in a loop. We're supposed to have a max size of 512MB per VM.
A max heap of 512 MB per VM doesn't mean that each VM will only use 512M, it means that it will grow to 512M + any extra memory required by the JVM itself. This can actually be quite large; I have JVMs that are half again as big as their heap in some cases[1].
Last time i did any WAS stuff was on Linux but on version 3 when it was new.. a long time ago. top - 14:04:46 up 2:09, 5 users, load average: 60.09, 18.03, 6.96 PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 4520 wasadmin 20 0 1178m 576m 4460 S 107 7.2 11:59.54 java 8943 wasadmin 20 0 566m 254m 4372 S 15 3.2 2:11.86 java
[snip] If you're going to use top to track down memory problems, please at least (a) sort by RES, which is what you care about, and (b) make sure top is recording all of the processes using significant memory. Your top display only shows a fraction of the 100+ processes, and is sorted by CPU use. Bit hard to guess what your culprits are from that. Something like ps -eao rss,pid,cmd | sort -n ...is probably more useful in determining where all your memory is going. It would be interesting to understand why one of your processes is running so hard on the CPU when the others are more modest. It may just be the workload, or it may be that trimming your heaps down has left it GC-thrashing, which will make your situation even worse. The fact you're deep in swap with Java processes, though, is going to destroy your performance. There's no way around that. Swap to VDISK, swap to physical disk, it doesn't matter. JVM + zLinux + zVM + Linux swapping is horrid for performance (zVM paging isn't much better). I have a couple of years of stress and production data that says so. [1] And yes, I mean real memory utilisation, not code segments and suchlike. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
