From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Hardy Subject: Re: Raid 1 install revealed poor HD performance (I think) Date: Tue, 17 May 2005 13:54:17 -0700 Message-ID: <428A59F9.5050908@h3c.com> References: <428A09A3.9000802@heyjay.com> <428A1924.8030801@heyjay.com> <428A2133.4080202@h3c.com> <428A594E.5080207@heyjay.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <428A594E.5080207@heyjay.com> Sender: linux-raid-owner@vger.kernel.org To: Jay Strauss Cc: Gordon Henderson , linux-raid@vger.kernel.org List-Id: linux-raid.ids Jay Strauss wrote: > I don't understand the above "whatever the disks need" portion of this > statement. Can you give me a little more detail? I did mean the hdparm settings, sorry I wasn't clearer > What settings am I to force? And to what values? I guess I'm asking, > are you saying just put the hdparm setting in a rc.local? If so, I'm > still stumped on what those settings need to be Well, the "typical" problem with regard to speed is DMA detection on your IDE chipset, which Gordon guessed (and which I would have). That needs to be set sometimes. I usually also set write-caching to off, although this does have a performance impact. Its also possible to twiddle some of the other hdparm settings, though these may or may not help. Things like multicount, IRQ unmasking. You can try any of them, then run bonnie++ or similar and see if they have an effect, and put them in rc.local (or similar) to make sure they stay in force across reboots. That's fine-grained tuning mostly though, and not really on topic for you as it appears you have something entirely different going on. What exactly is going on, I must admit, I don't know. :-/ -Mike