From mboxrd@z Thu Jan 1 00:00:00 1970 From: Karandeep Chahal Subject: Re: [PATCH 1/1] ib_srp: Infiniband srp fast failover patch. Date: Tue, 29 May 2012 18:27:46 -0400 Message-ID: <4FC54D62.3080003@ddn.com> References: <4FC53AAA.3060203@ddn.com> <4FC544FE.3000204@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4FC544FE.3000204@sgi.com> Sender: linux-kernel-owner@vger.kernel.org To: Michael Reed Cc: "linux-rdma@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "dillowda@ornl.gov" , "roland@kernel.org" , "sean.hefty@intel.com" List-Id: linux-rdma@vger.kernel.org Hi Michael, Yes, I tried reconnecting the targets and removing reinserting ib-srp. Thanks Karan On 05/29/2012 05:51 PM, Michael Reed wrote: > Did you subsequently reconnect the target and confirm appropriate behavior? > > > On 05/29/2012 02:07 PM, Karandeep Chahal wrote: >> Subject: [PATCH] Infiniband srp fast failover patch. Currently ib_srp does >> not do anything on receiving a DREQ from the target, it >> only sends a response back. Further it also does not >> monitor port (down) events. I have patched srp to remove >> scsi devices when a port down event is received or if the >> target sends a DREQ. Currently even though the target >> notifies the initiator of its intentions of going away, the >> initiator ignores that information. Later the initiator >> gets upset when the devices "suddenly" disappear resulting >> in srp initiating an error recovery process which takes a >> long time. This caused high failover latencies as compared >> to fibre channel. In my experiments with RHEL 6.0 and 6.2 I >> encountered failover time that exceeded 2 minutes and 20 >> seconds (despite tweaking /etc/multipath.conf and >> /sys/block/<>/timeout). With this patch the failover takes >> 30 seconds. I have tested this patch with and without a >> switch. >> >> Yours, etc. >> Karan >>