On Wed, Nov 02, 2011 at 07:37:17AM -0400, Bauer, Bobby (NIH/CIT) [E] wrote:
> Date:         Wed, 2 Nov 2011 07:37:17 -0400
> From: "Bauer, Bobby (NIH/CIT) [E]" <[email protected]>
> To: [email protected]
> Subject: Odd swap space behavior
>
> One of our Redhat servers got a LOT of activity yesterday and the swap space 
> looks funny to me.
>
> swapon -s
> Filename                                Type            Size    Used    
> Priority
> /dev/dasda2                             partition       1023976 3692    -1
> /dev/dasdb1                             partition       194964  420     2
> /dev/dasdc1                             partition       64976   152     1
> /dev/dasdd1                             partition       196596  25244   3
haven't done Linux on Z for a while, but I have always used the same "Priority" 
for the swapdisks
so that linux could spread out the IO to several disks (preferably on separate 
spindles).
This works well on x86 (real & VMware) and P-Series

<quote from http://www.vm.ibm.com/perf/tips/linuxper.html>
Swap extents of equal priority are used in round-robin fashion. Equal 
prioritization can be used to spread swap I/O across chpids and controllers, 
but if you are doing this, be careful not to put all the swap extents on 
minidisks on the same physical DASD volume, for if you do, you will not be 
accomplishing any spreading.
</quote>

I'd be interested to see what today's thinking is.

//rhi - now back to lurking
--
... Point and click  ...
... probably means that you forgot to load the gun ...
Have a nice day ;-) Richard Higson mailto:[email protected]

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