performance problem with amr driver and Perc 2/SC

[Prabhakaran, Rajesh]

  Even the data from our I/O performance analysis records shows similar
figure.
  PERC 2/SC(466) IO processor has no hardware XOR engine,so their will be
performance lag for RAID 5.Hence adding RAM might not help, migrating to
latest U320 controller, will significantly help.




-----Original Message-----
From: Jesse Guardiani [mailto:jesse at wingnet.net]
Sent: Thursday, November 06, 2003 11:44 AM
To: Moore, Eric Dean
Cc: freebsd-scsi at freebsd.org
Subject: Re: performance problem with amr driver and Perc 2/SC


On Thursday 06 November 2003 10:58, you wrote:
> Those are the optimal performance settings for
> those respective raid levels. Please go into
> control M and makesure those are your settings.

OK. I did this, and it more than doubled my sustainable
write speed!

I went from this:

    write             read
    2.05 MByte/Sec    12.59 MByte/Sec

To this:

    write             read
    6.31 MByte/Sec    13.49 MByte/Sec

Also, my peak Write went from about 3MB/Sec to 11MB/Sec,
and my peak Read went from about 13 MB/Sec to 18MB/Sec.

However, this still seems slow to me for an Ultra 2 SCSI
RAID-5 array. Is there anything else I can do to speed
things up? More RAM on the Perc 2/SC? A different SCSI
RAID controller altogether?

The PowerEdge 4300 only has a 32-bit PCI bus, but I
should still be able to achieve 20 MB/Sec Write and
20-40 MB/Sec Read with the right hardware, right?



> If your still having issue, please contact
> Atul or Rajesh as they are now maintaining this driver.
>
> Eric
>
> > On Thursday 06 November 2003 10:02, you wrote:
> > > My suggestion is to go into Control M Configuration Utility:
> >
> > OK. I understand that.
> >
> > > RAID5:  Write Back Cache, Normal Read Ahead, and Direct I/O
> > > RAID1:  Write Through Cache, Normal Read Ahead, and Direct I/O
> >
> > I'm not sure what you're trying to say here. As I stated in
> > my original
> > post, I'm running RAID5. What do you want me to do with the Write Back
> > Cache, Normal Read Ahead, and Direct I/O?
> >
> > Thanks!
> >

[...]

-- 
Jesse Guardiani, Systems Administrator
WingNET Internet Services,
P.O. Box 2605 // Cleveland, TN 37320-2605
423-559-LINK (v)  423-559-5145 (f)
http://www.wingnet.net


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