From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Robinson Subject: Re: slow mdadm reshape, normal? Date: Thu, 11 Jun 2009 21:50:35 +0100 Message-ID: <4A316E1B.9060607@anonymous.org.uk> References: <4A303C06.9080409@anonymous.org.uk> <20090610233659.GD30825@rlogin.dk> <20090611081909.GA16250@cthulhu.home.robinhill.me.uk> <20090611160741.GG30825@rlogin.dk> <20090611194552.GQ30825@rlogin.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090611194552.GQ30825@rlogin.dk> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 11/06/2009 20:45, Michael Ole Olsen wrote: [...] > it seems there is 21ms wait time for each request due to this pci slowness. (await is in miliseconds) > > might be the controller that isnt so fast to do simultaneous read and writes, > perhaps because its NCQ support might be bad? > > so I don't really have more ideas, except to buy a new controller card from a better brand (Adaptec) :( I have no personal experience of SIL SATA cards, but they've been mentioned before as being behind slowness. It's also possible something else on your PCI bus is choking things, so before you go and blow lots of real money on a better brand, what else is on your PCI bus? Please tell me the output of `lspci -tv` and the contents of /proc/interrupts twice (before and after a short delay, e.g. `cat /proc/interrupts ; sleep 5 ; cat /proc/interrupts`). Cheers, John.