Configuring Multipath I/O for Parallels Cloud Storage iSCSI Targets

Multipath I/O is a technique called to increase fault tolerance and performance by establishing multiple paths to the same iSCSI target. The figure below shows a typical multipath-enabled network configured for exporting Parallels Cloud Storage disk space over iSCSI.

In this example are three Parallels Cloud Server Hardware Nodes working in a Parallels Cloud Storage cluster. Two Nodes host one iSCSI target each while the third hosts two iSCSI targets. Each Hardware Node is assigned a static or dynamic IP address from the FrontNet 1 and the same from the FrontNet 2. In turn, each iSCSI target is assigned a static IP address from the FrontNet 1 and a static IP address from the FrontNet 2. In case one of the frontnets fails, the iSCSI targets will still be accessible via the other one.

To enable multipath I/O for a Parallels Cloud Storage iSCSI target, assign to it multiple IP addresses from different networks using the -a option. For example, for a Node connected to two networks, 192.168.10.0/24 and 192.168.20.0/24, run the following command:

# pstorage-iscsi create -n ps1 -a 192.168.10.101 -a 192.168.20.101