Currently ALUA device handler sends STPG command during failover and failback. Failover can be optimized by implicit failover (by not to sending STPG command), when 1 is passed as hwhandler parameter in multipath.conf. ex "2 alua 1". We may need to pass the parameter through module param for alua device handler to optimize failover if incase retain_attached_hwhandler set in multipath.conf and hwhandler is set with non-tpgs device handler ex: '1 rdac'.
Signed-off-by: Vijay Chauhan <[email protected]> Signed-off-by: Sean Stewart <[email protected]> --- --- a/drivers/scsi/device_handler/scsi_dh_alua.c.orig 2013-03-27 12:18:35.000000000 +0530 +++ b/drivers/scsi/device_handler/scsi_dh_alua.c 2013-03-27 13:23:16.000000000 +0530 @@ -710,6 +710,10 @@ static int alua_set_params(struct scsi_d return result; } +static uint optimize_stpg; +module_param(optimize_stpg, uint, S_IRUGO|S_IWUSR); +MODULE_PARM_DESC(optimize_stpg, "Send STPG command for Failover on non-preferred path(0=Yes,1=No). Default is 0."); + /* * alua_activate - activate a path * @sdev: device on the path to be activated @@ -731,6 +735,9 @@ static int alua_activate(struct scsi_dev if (err != SCSI_DH_OK) goto out; + if (optimize_stpg) + h->flags |= ALUA_OPTIMIZE_STPG; + if (h->tpgs & TPGS_MODE_EXPLICIT) { switch (h->state) { case TPGS_STATE_NONOPTIMIZED: -- -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
