MPIO is short for Multipath I/O. MPIO was made to support failover redundency and load balancing solutions. With MPIO if an unexpected failure of hardware occurs between the server and it's data storage it will not lead to an interuption of service or connectivity. When configured as a load balance solution MPIO can be used to share the load of client connections between two or more physical paths in order to avoid bandiwidth saturation of any one path that could lead to redunced or unsatisfactory performance for end users.
MPIO supports the following storage technologies:
During configuration the following supported options for Multipath I/O Load
Balancing Modes of operation will be presented:
Failover. With Failover based Load Balancing a primary path is configured
to be used at all times, unless it should become unavailable at some point.
In the event that the primary should become unavailable, then traffic will
be failed over to a configured secondary path. No load balancing takes place
with this configuration. It is strictly for the purposes of providing a redundant
secondary path in the event of any sort of failure to the primary path.
Failback. Will always prefer the primary, and will only direct to the
secondary when the primary is not available. Will always go right back to
the primary as soon as it is available again.
Round Robin. All available paths will be used in a balanced approach.
Round Robin with a subset of paths. Primary paths are specified,
and used in a Round Robin balancing manner. Secondary paths listed
in decreasing order of preference will only be used when the last of the
primary paths becomes unavailable
Dynamic Least Queue Depth. I/O will always use the path with the
smallest traffic load on it.
Weighted Path. Each path will be assigned a weight, and the path with
the lowest number will always be chosen as the priority path. The higher
the number, the lower the priority.
The default configuration is Round Robin when the storage controller is set for
active / active. When the storage controller is set for Asymmetric Logical Unit Access the default configuration is Failover.
Once installed MPIO can be launched from either of 2 locations: the ControlPanel or Administrative Tools. Some storage vendors have their own Device Specific Modules designed to work with W2K8. To install them, open the MPIO Control Panel Configuration Utility | DSM tab.
To install MPIO add it under server manager features: