[Wien] time difference among nodes

[Gavin Abo]

 From the top's sent before, it looks like the administrators might have 
configured the system with no swap:

r1i1n2

Swap:        0M total,        0M used,        0M free,    10563M cached

r1i1n3

Swap:        0M total,        0M used,        0M free,    23089M cached

Keep in mind that having swap might mean the difference between hurt 
performance and a hard crash under low memory [ 
http://unix.stackexchange.com/questions/190398/do-i-need-swap-space-if-i-have-more-than-enough-amount-of-ram 
].

On 9/29/2015 5:57 AM, Laurence Marks wrote:
>
> If it happens again, one thing to ask them to check is swap usage and 
> how much memory is cached. On some of my nodes I have noticed that 
> they do not always release cached memory, and can start swapping. If 
> this happens the job will get very slow. The commands to use to clear 
> the cache can be found at
> http://www.tecmint.com/clear-ram-memory-cache-buffer-and-swap-space-on-linux/ 
> or similar. (Needs root access.) Top can also show memory use.
>
> While there should be no need to do this, I have noticed that I need 
> to do it every 3hrs on 4 nodes - the other 20 don't need it. It is an 
> issue mainly for big calculations.
>
> Alternatively it was something else, a zombie, big log files or other 
> things. Rebooting gets rid of a lot of system caches and helps -- even 
> on my Android tablet every week or two. It's murky waters.
>
> ---
> Professor Laurence Marks
> Department of Materials Science and Engineering
> Northwestern University
> http://www.numis.northwestern.edu
> Corrosion in 4Dhttp://MURI4D.numis.northwestern.edu 
> <http://MURI4D.numis.northwestern.edu>
> Co-Editor, Acta Cryst A
> "Research is to see what everybody else has seen, and to think what 
> nobody else has thought"
> Albert Szent-Gyorgi
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20150929/250d85b8/attachment.html>