Re: [PATCH 1/1] ib_srp: Infiniband srp fast failover patch.

Michael Reed
2012-05-29T21:51:58Z

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
>