Re: 1x 3ware controllers vs. 2x 3ware controllers

["Jim Buttafuoco" <jim@contactbda.com>]

I get the same with dual XEON systems (I have 2 with Supermicro mb).  Reading on the net.  It seems that this is a 
know problem with people who are trying to build big systems.  No solution that I have seen.


---------- Original Message -----------
From: Mark Watts <mrwatts@fast24.co.uk>
To: Mikael Abrahamsson <swmike@swm.pp.se>
Cc: linux-raid@vger.kernel.org
Sent: Sun, 1 Aug 2004 16:01:46 +0100
Subject: Re: 1x 3ware controllers vs. 2x 3ware controllers

> > On Sun, 1 Aug 2004, Mark Watts wrote:
> > > This doesn't help explain why some of us are experiencing crap
> > > performance and un-responsive systems whereas others are having none of
> > > these problems  with the same 3Ware cards.
> >
> > On my 3ware equipped system running hw raid5 I get lousy write speeds
> > (approx 5-15 megabyte/s) on writes. I get great read speeds. I don't sit
> > directly on the console so I have no idea if the system is interactively
> > responsive or not, but I notice no problems being logged in via ssh.
> >
> > On the other hand, the 3ware volume is only used for bulk data storage,
> > the system, swap and other often needed data that is accessed and changed
> > often, I have stored on SCSI drives that are RAID1 or not RAIDed at all.
> >
> > I would never store the system/swap on a 3ware hw RAID5, that would be
> > disasterous for performance. Could you perhaps describe your system setup
> > in more detail?
> 
> Tyan S2845
> Dual Opteron 246 Processors
> 2GB DDR333 Ram
> nVidia FX5700
> 3Ware 8506-4LP 4 port SATA raid card
> 4x 250GB Maxtor hdds
> 
> RAID Configuration:
> 4-disk RAID-5 with 64K block size.
> 
> /dev/sda1 = / = 20GB
> /dev/sda2 = swap = 2048MB
> /dev/sda5 = /home = 100GB
> 
> All partitions (except swap) formatted as ext3.
> 
> Kernel - 2.6.8rc1, SMP for x86_64
> 
> Read performance is ok but nothing special.
> Writing larger files (anything that takes more than a few seconds) will cause 
> the system to 'stutter' as the write occurs.
> Longer writes (eg: copying ISO image about or formatting the rest of the 
> filesystem (600GB)) cause the system load to go high, very quickly.
> System is almost unusable at this stage but load returns to normal as the 
> write completes.
> 
> Slow write speeds is one thing, practically locking the system up while the 
> write occurs is another, unless I'm missing something obvious.
> 
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------- End of Original Message -------