[ewg][PATCH][0/2] SRP multipath failover within 60 seconds,

[Vu Pham]

The following patches assist SRP/dm-multipath to failover within 60 
seconds (bugzilla #577) without data corruption, read/write error

1. srp_disconnect_without_wait.patch - srp send disconnect request  
without waiting for CM timewait exit event since srp current does not 
re-use the cm_id and qp/cq of a connection (patch 
srp_1_recreate_at_reconnect.patch already in kernel_patches/fixes 
recreate the cmid, qp/cq for a connection at reconnect)
2. srp_qp_in_err_timer_reconnect_target.patch - when detecting a 
post_send/post_receive error, srp set qp_in_error, set a timer to 
reconnect to target, return SCSI_MLQUEUE_HOST_BUSY to lock the queue, 
and return DID_NO_CONNECT when target state is DEAD or REMOVED

Here is my multipath.conf
defaults {
        udev_dir                /dev
        polling_interval        5
        selector                "round-robin 0"
        path_grouping_policy    multibus
        getuid_callout          "/sbin/scsi_id -g -u -s /block/%n"
        prio_callout            /bin/true
        path_checker            readsector0
        rr_min_io               100
        rr_weight               priorities
        failback                immediate
        no_path_retry           5
        user_friendly_names     no
}
I also set srp_daemon.sh to rescan fabric every 60 seconds (instead of 
300 secs as default setting)

I ran data integrity test to /dev/mapper/<devices> and {disable path 1, 
sleep 90, enable path 1, sleep 60, disable path 2, sleep 90, enable path 
2, sleep 60} in the loop

RHEL5, 5.1 work very well (no data corruption, read/write failure report)
For SLES 10 sp1, it work well as long as I run *multipath* every 60 
secs. I think that I mis-configured the multipathd somehow (Here is how 
I set it up: using the same multipath.conf above, chkconfig 
boot.multipath on and chkconf multipathd on)

   -vu