Apparent strange disk behaviour in 6.0

Julian Elischer julian at elischer.org
Sat Jul 30 22:31:45 GMT 2005


Poul-Henning Kamp wrote:
> In message <42EBD958.6040402 at elischer.org>, Julian Elischer writes:
> 
> 
>>>If you know your queue-theory, you also know why busy% is
>>>a pointless measurement:  It represents the amount of time
>>>where the queue is non-empty.  It doesn't say anything about
>>>how quickly the queue drains or fills.
>>
>>exactly.. I'm trying to work out why teh read and write queues are empty for so 
>>much time in a transaction that SHOULD be disk bound....
> 
> 
> I am very confident that the disk statistics collected in GEOM don't lie:
> your disks are idle because nobody submits I/O requests.
> 
> Look at your scheduler...

I plan on doing just that..

I didn't say it was a problem in geom.. I just said that
it is worth investigating why there is no cannel saturation when in theory that
should be teh bottleneck.  I have noticed this before..

5 & 6 sometimes just don't seem to be "trying". they often have idle time when I 
would expect none.





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