Subject: RE: RAIDFrame and RAID-5
To: 'Greg Oster' <oster@cs.usask.ca>
From: Thomas Hertz <thomas@hz.se>
List: current-users
Date: 09/10/2003 16:52:27
> > My system presently has 512Mb of memory, so I guess this 
> has something 
> > to do with the added disk io that comes with swapping on the raid 
> > array.
> 
> Oh!!  Are you swapping to the RAID-5 array??  There are known 
> problems with doing that....

Actually, I'm not swapping to raid-5 even though I would like to swap to
a raid-10. But I used to swap on my raid-5, but I cannot say if that
made things worse or not.

I've recompiled with KMEMSTATS and really don't know what to look for.
During normal use (no parity rewrite, no reconstruction) vmstat -m tells
me that raidframe is using up to 515k memory, which sounds reasonable. I
then tried failing a component (raidctl -f), and noticed that suddenly
RAIDframe started using one 524288 byte size bucket in addition to the
64k buckets during normal operation. Also, RAIDframe uses up well over
30 megs of kernel memory (instead of the earlier 515k).
But then again, I don't know what's reasonable. :)

I'm gonna try to see what happens if I remove some of the NICs sometime
tonight. Could it be that the NIC driver (tlp) is behaving badly in some
way?

// Thomas Hertz