From mboxrd@z Thu Jan 1 00:00:00 1970 From: Spelic Subject: Re: on-off periodic hangs in scsi commands Date: Thu, 06 Jan 2011 22:06:51 +0100 Message-ID: <4D262EEB.9070303@shiftmail.org> References: <4D24BEC4.7040906@shiftmail.org> Mime-Version: 1.0 Content-Type: text/plain; format=flowed; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.isti.cnr.it ([194.119.192.4]:4977 "EHLO mx2.isti.cnr.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752831Ab1AFVHi (ORCPT ); Thu, 6 Jan 2011 16:07:38 -0500 Received: from SCRIPT-SPFWL-DAEMON.mx.isti.cnr.it by mx.isti.cnr.it (PMDF V6.5-x5 #31825) id <01NWBHL90GKWNG87AL@mx.isti.cnr.it> for linux-scsi@vger.kernel.org; Thu, 06 Jan 2011 22:06:37 +0100 (MET) Received: from conversionlocal.isti.cnr.it by mx.isti.cnr.it (PMDF V6.5-x5 #31825) id <01NWBHL8B5F4NG87AJ@mx.isti.cnr.it> for linux-scsi@vger.kernel.org; Thu, 06 Jan 2011 22:06:35 +0100 (MET) In-reply-to: <4D24BEC4.7040906@shiftmail.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Spelic Cc: "linux-scsi@vger.kernel.org" , open-iscsi@googlegroups.com, scst-devel@lists.sourceforge.net On 01/05/2011 07:56 PM, Spelic wrote: > Hello > I am on kernel 2.6.36.2 (but I think I saw this problem also long > time ago on 2.6.31) > I am having problems of greatly reduced throughput to scsi devices > > ...with 3ware... > ...and now with iscsi... Please disregard the whole iSCSI thing, iSCSI works perfectly! I forgot I had a firewall test running simultaneously, I'm just stupid... let's not even talk about it :-( The 3ware thing is real though, but I guess it's some kind of 3ware bug. Difficult to say for sure until I can get my hands on another controller. Strange thing only one MD array has that problem even though there are other similar MD raid5 arrays on the same controller and other identical controllers. It can't be a damaged disk because writes get stuck cyclically on all 6 drives of that array. Even cables can't be: they are cables for 4 drives each, and 2 drives are together with other 2 drives on another MD array which doesn't show the problem. Is there any way to tell Linux to poll a PCI device even if it hasn't received an interrupt from it? If I could poll the controller every, say, 0.2 sec I could test if the problem goes away. Thank you