Multipath Configuration

Citrix
Audience
Public
Technology Integrations
Citrix
Source Type
Documentation

The Multipath Policy defines how the host distributes IOs across the available paths to the storage. The Round Robin (RR) policy distributes IOs evenly across all Active/Optimized paths. A newer MPIO policy, queue-length, is similar to round robin in that IOs are distributed across all available Active/Optimized paths, however, it provides some additional benefits. The queue-length path selector will bias IOs towards paths that are servicing IO quicker (paths with shorter queues). In the event that one path becomes intermittently disruptive or is experiencing higher latency, queue-length will prevent the utilization of that path reducing the effect of the problem path.

These settings are applicable to Fibre Channel and iSCSI, and should be added to your multipath.conf file:

  • XenServer 6.1, 6.2, 6.5 - /etc/multipath.conf
  • XenServer 7.x, 8.x - /etc/multipath.xenserver/multipath.conf

XenServer Version

Multipath Recommendations

XenServer 7.x

XenServer 8.x

In ActiveCluster configurations, Pure Arrays make use of ALUA to handle path state changes in the event of a loss of replication link between arrays.


defaults {
    polling_interval      10
}

       device {
                vendor                "PURE"
                product               "FlashArray"
                path_selector         "queue-length 0"
                path_grouping_policy  group_by_prio
                path_checker          tur
                fast_io_fail_tmo      10
                dev_loss_tmo          60
                no_path_retry         0
                hardware_handler      "1 alua"
                prio                  alua
                failback              immediate
        }
}

XenServer 6.5

 

 device {
                vendor                  "PURE"
                product                 "FlashArray"
                path_selector           "queue-length 0"
                path_grouping_policy    multibus
                rr_weight               uniform
                prio                    const
                rr_min_io_rq            1
                path_checker            tur
        }

XenServer 6.2

 

device {
                vendor                  "PURE"
                product                 "FlashArray"
                path_selector           "round-robin 0"
                path_grouping_policy    multibus
                rr_weight               uniform
                prio                    const
                rr_min_io_rq            1
                path_checker            tur
        }

XenServer 6.1

 

device {
      vendor                  “PURE”
      product                 “FlashArray”
      path_grouping_policy    multibus
      path_checker            tur
      rr_min_io               1
      path_selector           “round-robin 0”
      no_path_retry           0
      fast_io_fail_tmo        3
      dev_loss_tmo            30
      prio                    alua
      }