Hi Winne,
I asked this question to the DPM developers on your behalf. They have
kindly replied and this is what you got:
We did a small performance test with DPM, which has shown that
most of the CPU was used for X509 authentication. So if there
would be many small requests, then having more CPU would be
useful. However, as you have described, with larger files the
CPU is typically not a problem, i.e. I would suggest 4 only.
https://twiki.cern.ch/twiki/bin/view/LCG/Scalability_DPM
On the other hand I think more the RAM you have the better.
If it is not used in the user space, then the OS can use it
for caching. To make use of the extra RAM in user space you should run the
box with real x86_64 OS and software.
And a final remark: we have seen that ext3 does not perform
well with file deletion, so I would suggest using xfs on a
storage at this size.
I always preferred more RAM then CPUs on the DPM head node but I wanted
to confirm. We are actually going for a 4-core, maybe dual-core node for
our new head node.
Hope this help.
Cheers,
Santanu
Bly, MJ (Martin) wrote:
> Winne,
>
> I waited for someone running DM to respond but since they haven't...
>
> Comments in-line...
>
> Martin.
>
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