HP 166207-B21 Advanced Data Guarding Option Software Reference Guide - Page 19

System Setup 9. Change the stripe size if desired. The "Optimizing the Stripe Size" section discusses the stripe sizes that are most useful for various applications. 10. Press the Esc key to save the changes and begin the migration. Migrating a RAID ADG Volume to Another Controller You can migrate a RAID ADG logical volume only if both controllers support RAID ADG. If the new controller supports RAID ADG but does not have it enabled, the write cache is disabled. In this case, though, the data can still be read or copied. Assigning Online Spares after System Configuration Assigning online spares to a fault-tolerant configuration provides additional protection against hard drive failure. You can: • Assign a different online spare to each array on the controller. • Share one online spare among several arrays on the same controller, for efficient use of drive capacity. • Assign several online spares to just one array. • Share several online spares among several arrays; this method provides the greatest amount of protection for the largest number of arrays. IMPORTANT: Assigning several spares to an array lets you postpone replacement of faulty drives, but it does not increase the fault-tolerance level of any logical drives in the array. For example, a logical drive in a RAID 5 configuration suffers irretrievable data loss if two physical drives fail simultaneously, regardless of the number of spare drives assigned. Any drive that you assign as an online spare for an array operates as the spare for every fault-tolerant logical drive within the array. To assign online spares: 1. Check that at least one hard drive containing no data is connected to the controller that contains the array. Compaq Advanced Data Guarding Option Software Reference Guide 2-7