From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: Getting device-mapper failure notifications Date: Wed, 24 Feb 2016 12:25:50 -0500 Message-ID: <20160224172550.GB15480@redhat.com> References: <56CD38FD.9010209@redhat.com> <56CD8527.5000702@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <56CD8527.5000702@suse.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Hannes Reinecke Cc: dm-devel@redhat.com List-Id: dm-devel.ids On Wed, Feb 24 2016 at 5:25am -0500, Hannes Reinecke wrote: > On 02/24/2016 01:00 PM, Andy Grover wrote: > > On 02/01/2016 11:07 PM, Avishay Traeger wrote: > >> Hi all, > >> I have a system where various configurations are possible - iSCSI/FC, > >> single paths and multiple. For multiple I of course use device-mapper. > >> I was wondering if it was possible to: > >> 1. use it for cases where I have a single path. > >> 2. create a monitoring process that can take some action (e.g., send a > >> notification via message queue) in the case of some failure that would > >> normally cause failover. > > > > Does dm-multipath support a single path? I don't know... > > > Pshaw. > Of course it does. > > (Might be that RH has some magic disallowing that, but certainly there's > nothing in the source which forbids it. In fact I recommend it when > using iSCSI) No, RH provided dm-multipath doesn't disallow single path multipath. Not sure why you engage in raising such doubt -- red hat follows upstream. period. multipathd can be configured to look for multiple paths ('find_multipaths yes' in multipath.conf) but there is nothing in the kernel disallowing the use of dm-multipath with a single path.