vinum performance

[Jason Andresen]

Craig Boston wrote:
> On Mon, 2003-03-31 at 15:41, Jason Andresen wrote:
> 
>>(Both of these were on previously untouched files to prevent any 
>>caching, and the "write" test is on a new file, not rewriting an old one)
>>Write speed:
>>81920000 bytes transferred in 3.761307 secs (21779663 bytes/sec)
>>Read speed:
>>81920000 bytes transferred in 3.488978 secs (23479655 bytes/sec)
>>
>>But on the RAID5:
>>Write speed:
>>81920000 bytes transferred in 17.651300 secs (4641018 bytes/sec)
>>Read speed:
>>81920000 bytes transferred in 4.304083 secs (19033090 bytes/sec)
> 
> 
> Disclaimer: IANAVE (I am not a Vinum Expert)
> 
> What block size are you using with dd?  If your bs= is less than your
> RAID stripe size, it seems like it would end up doing unnecessary
> read-modify-write cycles...

Commands used:

dd if=/dev/zero of=test bs=8192 count=1000

and

dd if=random_unused_file_larger_than_80MB of=/dev/null bs=8192 \ count=10000

My stripe size is 384k.

-- 
   \  |_ _|__ __|_ \ __| Jason Andresen        jandrese at mitre.org
  |\/ |  |    |    / _|  Network and Distributed Systems Engineer
_|  _|___|  _| _|_\___| Office: 703-883-7755