From: Daryll Strauss <daryll@valinux.com>
To: Wilfried Weissmann <Wilfried.Weissmann@gmx.at>
Cc: Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: software raid does not do parallel reads under 2.4?
Date: Fri, 24 Aug 2001 10:14:39 -0700 [thread overview]
Message-ID: <20010824101439.C1717@newbie> (raw)
In-Reply-To: <20010823234218.B12873@cerebro.laendle> <15238.11161.492557.264988@notabene.cse.unsw.edu.au> <3B868874.B89B04DE@gmx.at>
In-Reply-To: <3B868874.B89B04DE@gmx.at>; from Wilfried.Weissmann@gmx.at on Fri, Aug 24, 2001 at 07:01:40PM +0200
On Fri, Aug 24, 2001 at 07:01:40PM +0200, Wilfried Weissmann wrote:
> I experienced some performance loss when moving from kernel 2.4.4 to
> 2.4.7-ac3 regarding ide harddisks. I am useing the hpt ataraid driver
> which does pretty much the same thing as the md disk striping driver.
> I/O speed of the raid volume is about as fast as accessing a single
> drive.
> There were a lot of ide reports some time ago. Maybe they where problems
> with concurrent I/O operations...?
I'm seeing similar behavior with SCSI. I've got two SCSI channels. If I
run two dd's each talking to disks on different channels, I get 2x disk
bandwidth. If I run two dd's talking to disks on the same channel I get
1x disk bandwidth. This is with 2.4.9, but I haven't isolated which
kernel versions cause this.
This system has 8 U160 disks spread over 2 U160 channels and it hasn't
been deployed yet, so if I can help with testing, let me know.
- |Daryll
next prev parent reply other threads:[~2001-08-24 17:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-08-23 21:42 software raid does not do parallel reads under 2.4? Lehmann
2001-08-24 10:25 ` Neil Brown
2001-08-24 17:01 ` Wilfried Weissmann
2001-08-24 17:14 ` Daryll Strauss [this message]
2001-08-24 20:23 ` Lehmann
2001-08-24 20:22 ` Lehmann
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