[Beowulf] disabling swap on cluster nodes?

[Prentice Bisbal]

It makes perfect sense. My BG/P nodes don't swap and only have 512 
MB/core. But before I do it myself, I want to see if anyone else did 
this with negative effects.

Truly diskless nodes would have to be swapless, but a lot of people use 
'diskless' to mean no OS installed locally, but there's still a disk in 
the node for local scratch or swap.

I did some googling searching this afternoon, and I saw a lot of people 
recommending it for HPC nodes, but it sounded like they were talking 
based on theory rather than actual practice which is why I'm looking for 
actual practitioners.

One person already replied off list and says he does this without any 
issues.

Prentice

On 02/06/2015 05:38 PM, Novosielski, Ryan wrote:
> It does seem like a good idea on the face of it. I would have to check 
> if we do that, but I know that the jobs we tend to run don't happen to 
> come close to using all of the physical memory on the machines anyway, 
> so there ought not really be an impact, I'd think.
>
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> On Feb 6, 2015, at 17:34, Prentice Bisbal <prentice.bisbal at rutgers.edu 
> <mailto:prentice.bisbal at rutgers.edu>> wrote:
>
>> Do any of you disable swap on your compute nodes?
>>
>> I brought this up in a presentation I gave last night on HPC system
>> administration, but realized I never actually did this, or know of
>> anyone who has. I would tweak the vm.overcommit_memory setting, but
>> that's not the same as disabling swap altogether. I'd like to try doing
>> this in the future, but I prefer to learn from someone else's mistakes
>> first.
>>
>>
>> -- 
>> Prentice
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