Compaq Proliant CISS slow writes

[Marc G. Fournier]

Not sure if this is standard, but on an idle machine (ie. just set it up, 
nothing running on it yet), with RAID1+0 across 4 drives:

Writing the 853 Megabyte file, 'iozone.tmp'...15.656250 seconds
Reading the file...3.921875 seconds

IOZONE performance measurements:
         57129601 bytes/second for writing the file
         228063191 bytes/second for reading the file

The server is a new DL360 G4p, drives are SAS ...

On Sat, 4 Feb 2006, Ivan Voras wrote:

> I need to get a Proliant machine with 2 P3 processors running FreeBSD 6. I 
> don't know much about the machine, I think it's ML 380 G2 or close to that, 
> but I have physical access. So far, everything is fine (once the inability to 
> boot from CD-ROM is circumvented), except one "detail": horrible write 
> performance on its CISS 5 RAID5 array. I get ~75MB/s burst (large blocks) 
> reads, and only 5MB/s burst writes. I know how RAID5 works, but still, this 
> is bad. The machine has been running Linux before this and performance was Ok 
> - I didn't benchmark it but the "feeling" when working on it was normal, 
> while on FreeBSD it's noticably slow in mixed read/write load.
>
> Is there anything I can try to improve this? In the verbose boot log there's 
> a line that says the controller supports "simple, performant and MEMQ" modes, 
> and the one that's used is "simple" - does this have any influence? If so, 
> how to change it?
>
> Thanks!
>

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Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy at hub.org           Yahoo!: yscrappy              ICQ: 7615664