From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: Re: [LSF/MM ATTEND][LSF/MM TOPIC] Multipath redesign Date: Thu, 14 Jan 2016 11:09:36 -0800 Message-ID: <5697F270.3070205@sandisk.com> References: <56961493.5010901@suse.de> <20160113175239.GE24960@octiron.msp.redhat.com> <56974D80.2020803@suse.de> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <56974D80.2020803@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: device-mapper development , Hannes Reinecke , Benjamin Marzinski List-Id: dm-devel.ids On 01/13/2016 11:25 PM, Hannes Reinecke wrote: > On 01/13/2016 06:52 PM, Benjamin Marzinski wrote: >> On Wed, Jan 13, 2016 at 10:10:43AM +0100, Hannes Reinecke wrote: >>> c) implement block or scsi events whenever a remote port becomes >>> unavailable. This removes the need of the 'path_checker' >>> functionality in multipath-tools. >> >> I'm not convinced that we will be able to find out when paths come back >> online in all cases without some sort of actual polling. Again, I'd love >> this to be simpler, but asking all the types of storage we plan to >> support to notify us when they are up and down may not be realistic. > > Currently we have three main transports: FC, iSCSI, and SAS. Hello Hannes, Since several years the Linux SRP initiator driver also has reliable and efficient H.A. support. The IB spec supports port state change notifications. But whether or not port state information affects the path state should be configurable. Several IB users wouldn't like it if port state information would affect the path state because the time during which a port is down can be shorter than the time during which an IB HCA keeps retrying to send a packet. Bart.