Compaq Proliant CISS slow writes

[Philippe Pegon]

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!

do you have write cache on your Smart Array 532 ?
I had the same problem last year with a Smart Array 642, this controller 
is sold without write cache and we needed to buy the couple 
battery/write cache for it to have good write performance.

--
Philippe Pegon