From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tim Small Subject: Re: Data-check brings system to a standstill Date: Fri, 18 Jun 2010 18:10:24 +0100 Message-ID: <4C1BA880.1050609@seoss.co.uk> References: <4C0FCFCD.4070201@quo.to> <4C19015B.3020807@tmr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4C19015B.3020807@tmr.com> Sender: linux-raid-owner@vger.kernel.org To: Bill Davidsen Cc: Jordan Russell , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 16/06/10 17:52, Bill Davidsen wrote: >> As of kernel 2.6.32 (I didn't see this when I was running 2.6.24-2.6.27 >> previously), the kernel also emits "hung task" warnings every few >> minutes while the data-check is in progress: >> >> # echo check > /sys/block/md1/md/sync_action >> # cat /var/log/messages > Have things switched to AHCI (or similar SATA controller) with NCQ since? If so, do you drives have buggy firmware which makes them suck with sequential reads when NCQ is enabled? See the libata wiki for details - you can try disabling NCQ (or limiting queue depth to 2, or whatever) to test it.... Tim. -- South East Open Source Solutions Limited Registered in England and Wales with company number 06134732. Registered Office: 2 Powell Gardens, Redhill, Surrey, RH1 1TQ VAT number: 900 6633 53 http://seoss.co.uk/ +44-(0)1273-808309