IBM server x 3850 (4X8core Xeon 7560), RedHat 5.6, free -mt on terminal shown only 32 GB?

Question

I'm remotely SSH-ing an IBM server-x running RedHat 5.6. The server has 4 CPUs with 8 cores each, which is verified by cat /proc/cpuinfo

But free -mt show only the 32 G-RAM (which is correct for one CPU), not the expected 128 GB. Why is that? Is there some other way to check available memory ?

Thanks.

I did, and found out a non-NUMA aware xen-kernel trolling my dom0. I would have checked your answer though if it wasn't a comment :-) Thanks! — avinamal, Sep 07 '11 at 23:31
Can you still post the output and fix for future generations? — MikeyB, Sep 08 '11 at 00:16

score 3 · Accepted Answer · answered Sep 07 '11 at 23:46

3

Check the output of numactl --hardware.

It may give you a clue as to what's going wrong.

answered Sep 07 '11 at 23:46

MikeyB

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score 0 · Answer 2 · answered Sep 08 '11 at 05:50

So with MikeyB's help, the problem was pinned down to a non NUMA aware kernel.

$> numactl --show

No NUMA support available on this system.

Next step: consult kernel's docs and find out how to turn it NUMA aware (in xen, numa=on will do it), or init a kernel which is NUMA-aware by default S.A RHEL5.6. Both worked for me.

IBM server x 3850 (4X8core Xeon 7560), RedHat 5.6, free -mt on terminal shown only 32 GB?

2 Answers2