this might well be. I never tried to touch the RAID at all after getting 
it to work.
It's a LaCie RAID TX8000 and the documentation really s*cks.

I still don't quite understand why this should be the case. My 
presumably naive  assumption is that the RAID got a 16MB cache, which is 
battery  buffered. It will fill up the cache until it can write a block 
and then it will write the block, but I am probably far to naive.

Looking at the RAID there seems to be thousands of parameters ... :-) 
and I guess I have to reformat the RAID in order to change the size of 
the stripes. What would be a reasonable size for a stripe? (Probably 
something along the r/wsize for NFS, e.g. 8k?)

Thanks

Dominik




On Mittwoch, Mai 9, 2001, at 04:59  Uhr, Manuel Bouyer wrote:

> On Sun, May 06, 2001 at 03:11:58PM +0200, Dominik Westner wrote:
>> Actually there seems to be some difference between  the raid and an
>> internal disk.
>> While the internal disk is locally much slower it performs better
>> through NFS compared to the raid.
>>
>> Internal disk local performance:
>> boo#  dd bs=1024k count=32 if=/dev/zero of=tmpfile
>> 32+0 records in
>> 32+0 records out
>> 33554432 bytes transferred in 7 secs (4793490 bytes/sec)
>> boo#
>> boo# dd bs=1024k count=32 of=/dev/null if=tmpfile
>> 32+0 records in
>> 32+0 records out
>> 33554432 bytes transferred in 1 secs (33554432 bytes/sec)
>>
>>
>> Internal disk NFS performance:
>> [icebox:/tmp/boo/tmp] root# dd bs=1024k count=32 if=/dev/zero 
>> of=tmpfile2
>> 32+0 records in
>> 32+0 records out
>> 33554432 bytes transferred in 26 secs (1290555 bytes/sec)
>> [icebox:/tmp/boo/tmp] root# dd bs=1024k count=32 of=/dev/null 
>> if=tmpfile2
>> 32+0 records in
>> 32+0 records out
>> 33554432 bytes transferred in 1 secs (33554432 bytes/sec)
>>
>> Is there a way to make the raid perform better through NFS? I mean for
>> NetBSD it's just some scsi device. I don't see how this could be tuned.
>
> I suspect your RAID device doesn't like small transactions, it needs to
> read/write full blocks several time, as NFS does fileops of size 
> smaller than
> a stripe.
> Can you change the size of a stripe on the RAID device itself ?
>
> --
> Manuel Bouyer, LIP6, Universite Paris VI.           
> Manuel.Bouyer@lip6.fr
> --