Determine whether you want I/O bus level protection based on the following:
- To keep your system available when an I/O bus fails.
- To concurrently repair a failed disk unit.
To achieve I/O bus protection, all disk units must have a mirrored unit attached to a different I/O bus. This figure shows I/O bus protection. The two storage units make a mirrored pair. With I/O bus protection, the system can continue to operate if one I/O bus fails. If the IOA or the IOP fails, the system cannot access data on either of the disk units, and the system is unusable.
This figure shows the elements of I/O bus protection: one bus, connected to one I/O processor, connected to one IOA, with two or more I/O buses, each attached to a separate disk unit.
