Storage multipathing

XenServer supports dynamic multipathing for Fibre Channel and iSCSI Storage Repositories.

Multipath I/O is a fault-tolerance and performance enhancement technique. Multipathing solutions use redundant physical path components (such as adapters, cables, and switches) to create logical paths between the server and the storage device. In the event that one or more of these components fail, causing the path to fail, multipathing logic uses an alternate path for I/O so that virtual machines can still run.

By default, multipathing uses round robin mode load balancing, so both paths will have active traffic on them during normal operation.

In the following figure, you can see a XenServer host with multipathing enabled—each Host Bus Adapter is connected to a switch using a different path.

Remember that your FC and iSCSI storage devices must support multipathing too.

If your storage devices do not support multipath, you can also use NIC bonding in order to provide redundancy for...