Storage multipathing 编辑

Dynamic multipathing support is available for Fibre Channel and iSCSI storage back-ends.

Citrix Hypervisor uses Linux native multipathing (DM-MP), the generic Linux multipathing solution, as its multipath handler. However, Citrix Hypervisor supplements this handler with additional features so that Citrix Hypervisor can recognize vendor-specific features of storage devices.

Configuring multipathing provides redundancy for remote storage traffic if there is partial connectivity loss. Multipathing routes storage traffic to a storage device over multiple paths for redundancy and increased throughput. Multipathing is an active-active configuration. By default, multipathing uses either round-robin or multibus load balancing depending on the storage array type. All routes have active traffic on them during normal operation, which results in increased throughput.

Important:

We recommend that you enable multipathing for all servers in your pool before creating the SR. If you create the SR before enabling multipathing, you must put your servers into maintenance mode to enable multipathing.

NIC bonding can also provide redundancy for storage traffic. For iSCSI storage, we recommend configuring multipathing instead of NIC bonding whenever possible.

Multipathing is not effective in the following scenarios:

• NFS storage devices
• You have limited number of NICs and need to route iSCSI traffic and file traffic (NFS or SMB) over the same NIC

In these cases, consider using NIC bonding instead. For more information about NIC bonding, see Networking.

Prerequisites

Before enabling multipathing, verify that the following statements are true:

• Multiple targets are available on your storage server.

  For example, an iSCSI storage back-end queried for sendtargets on a given portal returns multiple targets, as in the following example:

    iscsiadm -m discovery --type sendtargets --portal 192.168.0.161
    192.168.0.161:3260,1 iqn.strawberry:litchie
    192.168.0.204:3260,2 iqn.strawberry:litchie