From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Reed Subject: Re: [PATCH 1/1] ib_srp: Infiniband srp fast failover patch. Date: Tue, 29 May 2012 15:53:05 -0700 Message-ID: <4FC55351.6020503@sgi.com> References: <4FC53AAA.3060203@ddn.com> <4FC544FE.3000204@sgi.com> <4FC54D62.3080003@ddn.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4FC54D62.3080003-LfVdkaOWEx8@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Karandeep Chahal Cc: "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "dillowda-1Heg1YXhbW8@public.gmane.org" , "roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" , "sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org" List-Id: linux-rdma@vger.kernel.org Thank you for clarifying! On 05/29/2012 03:27 PM, Karandeep Chahal wrote: > 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 >>> > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html