[rescue] playing with the new E250 ... disk performance vs. old PeeCee

Joshua Boyd jdboyd at jdboyd.net
Mon Dec 18 09:16:52 CST 2006

On Sat, Dec 16, 2006 at 05:28:07PM -0500, Magnus wrote:

> Sun:
>   Timing O_DIRECT cached reads:   732 MB in  2.01 seconds = 364.52 MB/sec
>   Timing O_DIRECT cached reads:   744 MB in  2.00 seconds = 371.23 MB/sec
>   Timing O_DIRECT cached reads:   728 MB in  2.00 seconds = 363.98 MB/sec
>   Timing O_DIRECT disk reads:   52 MB in  3.03 seconds =  17.15 MB/sec
>   Timing O_DIRECT disk reads:   56 MB in  3.10 seconds =  18.06 MB/sec
>   Timing O_DIRECT disk reads:   50 MB in  3.04 seconds =  16.45 MB/sec

> Do the low direct disk read numbers for the Sun box surprise anyone?  Am 
> I hitting a limitation of the SCSI controller here?  I'm not too 
> familiar with the E250 platform yet and I was thinking maybe it had a 
> faster SCSI controller than that.  Looks more like it maxes out at 20MB/sec.

I get about that speed on three of the harddrives in my e250, but
somewhat better speed on two 180 gig drives.  Still, you would only get
about 2x that speed.  
> If I'm maxing out on the SCSI controller, is there a decent PCI SCSI 
> card that is "correct" for these boxes that I can search for on eBay and 
> plug into my hot swap backplane to achieve better performance?

That would be nice, if possible.  It will be interesting to see what
others say.
Once you figure out why your disk is behaving poorly, you could fairly
affordably add an external 711 array and stripe across two channels
then.  Assuming you have space for a 711.  I don't, so I'm thinking of
something like a D130 instead.

Joshua D. Boyd
jdboyd at jdboyd.net

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