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

[Karandeep Chahal]

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
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