From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stan Hoeppner Subject: Re: How to prefer some devices over others in raid Date: Thu, 02 Jan 2014 08:30:24 -0600 Message-ID: <52C57800.3090802@hardwarefreak.com> References: <52C2E00B.90406@hardwarefreak.com> <52C44708.3030307@hardwarefreak.com> Reply-To: stan@hardwarefreak.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Tomas M Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 1/1/2014 12:00 PM, Tomas M wrote: >> Your initial post suggested you knew which drive was flaky. Now you >> indicate you don't know which, if any, is flaky. This suggests you have >> no idea why your array is slow. > > Well, I always have an indication which drive is flaky, based on dmesg > output (e.g. hard resetting ATA3 link, etc). However, sometimes it > reports that more than one drive has problems [snip] Full stop. Random resets on multiple links indicates a backplane (if present), HBA/controller, or cable problem, not a drive problem. If you're using an HBA+backplane with an SFF-8087 4x multilane cable, or a breakout cable, the problem could be as simple as a lose connection at the SFF-8087 multilane connector, or a cable gone bad. If you have multiple discrete SATA cables, one per drive, this indicates a problem with the controller/HBA. Ergo, if you have a multilane cable, unplug/replug it and see if that helps. If not, replace it. If that doesn't solve the problem, replace the HBA. If replacing the HBA doesn't solve it, replace the backplane. If you have discrete cables, replacing the HBA should fix the problem. If you have discrete cables and are using motherboard SATA ports, you'll need to acquire an HBA and cease using the motherboard ports. -- Stan