On Feb 23, 2011, at 3:42 AM, Rudi Ahlers <Rudi@xxxxxxxxxxx> wrote:
> On Wed, Feb 23, 2011 at 9:06 AM, yonatan pingle
> <yonatan.pingle@xxxxxxxxx> wrote:
>> you should have a look at your I/O disk status.
>>
>> try with iostat -dx 5 to see the disk utilization info over time.
>> when it comes to slowdown on a virtual environment on a Desktop grade
>> machine, i suspect disk I/O latency and bottleneck as a cause.
>
> Thanx, I don't know how to interpret the results (yet), but here's the
> current output:
>
> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz
> avgqu-sz await svctm %util
Knowing the columns helps here,
rrqm/s and wrqm/s, mean read/write requests merged a second, shows how well scheduler is merging contiguous io operations
r/s and w/s, read/write io operations a second
rsec/s and wsec/s, read/write sectors a second, I usually use the -k option so it displays as kilobytes a second
avgrq-sz, shows average request size in the unit of choice, here being sectors, I wish it'd separate reads from writes, but oh well
avgqu-sz, average amount of io operations waiting for service, smaller is better
await, average time an io operation waited on queue to be serviced in ms, again smaller is better
svctm, last time it took to service an io operation, how long the drive took to perform the operation from when it left queue to when a result was returned
%util, the estimated drive utilization based on svctm, await and avgqu-sz
For lockups though I'd look at dmesg and xen log, xmlog I think is the command.
The number one reason for lockups though is most likely memory contention between domUs and dom0.
What are you running in dom0? What are your memory reservations like?
-Ross
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