How RAID 10 protection works

This topic describes how RAID 10 protection works.

The IOA determines how parity sets are formed. RAID 10 protection uses two disk units in each parity set. Optimal performance, capacity, and balancing are achieved with any of the parity optimization settings.

It is not possible to include more disk units of the same capacity in a parity set after device parity protection is started. To add disk units to an existing I/O adapter that is running RAID 10, the system requires that you start a new parity set, rather than include them in an existing parity set.

In IBM® Navigator for i, you can view the properties of each disk unit. If the protection status of a disk unit is unprotected, it is not protected by device parity protection or mirroring and might be eligible to start a new parity set. An unprotected unit also has a model number of 050.

A write cache is included in the IOA for each parity set to improve performance of interactive write workloads.

Note: Starting RAID 10 protection before the disk units are added to a disk pool significantly reduces the time that it takes to start device parity protection and configure the disk units.