From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [multipath] meaning of "no_path_retry nn" Date: Mon, 07 Sep 2009 16:43:19 +0200 Message-ID: <4AA51C07.4080104@suse.de> References: <7ujn84$746nl@dgate20u.abg.fsc.net> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <7ujn84$746nl@dgate20u.abg.fsc.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development List-Id: dm-devel.ids Diedrich Ehlerding wrote: > I would appreciate an explanation of "no_path_retry nn" parameter in=20 > multipath.conf. Probably I misunderstood it as a number of seconds.=20 >=20 > I am setting up a software mirror (mdadm) on top of an EMC Clariion=20 > configuration for desaster protection. The Clariions are recognized by=20 > multipath properly; it seems to be set up with "no_path_retry 60"=20 > (according to multipath -t). I had no further settings in=20 > multipath.conf; this seems to be hardcoded into multipath.=20 >=20 > However, If I disconnect one Clariion, th mirror doesnt break -=20 > multipath detects that all paths are failed and tells me that it will=20 > now wait for 60 retries. These 60 retries seem to last very long;=20 > atfter 5 minutes, it didnt complete.=20 >=20 > Evertyhing works fine if I set up a multipath.conf containing the=20 > Clariion settings from multipath -t and modify them to=20 > "no_path_retry fail" and "features 0 fail_if_no_path". But even if I=20 > just reduce the default settings to no_path_retry 2 the mirror doesnt=20 > break - the IOs seem to hang indefinitely (well, I lost patience after=20 > ~5 minutes). >=20 > Probably I misunderstood "no_path_retry 60" - does that mean seconds,=20 > or minutes, or what else? Is anything except "fail" a useful setting in= =20 > mirrored configurations?=20 >=20 > system is a Suse with multipath-tools-0.4.7-34.43 >=20 Please note that there is a bug in the multipath-tools on suse which prevents the no_path_retry option from working correctly. Please install the latest maintenance update. Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: Markus Rex, HRB 16746 (AG N=FCrnberg)