Planning: MD3200i Series Storage Array Terms and Concepts 43The segment size or stripe element size specifies the size of data in a stripewritten to a single disk. The storage array supports stripe element sizes of 8,16, 32, 64, 128, 256, and 512 KB. The default stripe element size is 128 KB.Stripe width, or depth, refers to the number of disks involved in an arraywhere striping is implemented. For example, a four-disk group with diskstriping has a stripe width of four.NOTE: Although disk striping delivers excellent performance, striping alone doesnot provide data redundancy.Virtual Disk OperationsVirtual Disk InitializationEvery virtual disk must be initialized. Initialization can be done in theforeground or the background. A maximum of four virtual disks can beinitialized concurrently on each RAID controller module.Background InitializationThe storage array executes a background initialization when the virtual disk iscreated to establish parity, while allowing full host server access to the virtualdisks. Background initialization does not run on RAID 0 virtual disks. Thebackground initialization rate is controlled by MDSM. To change the rate ofbackground initialization, you must stop any existing backgroundinitialization. The rate change is implemented when the backgroundinitialization restarts automatically.Foreground InitializationThe storage array supports foreground initialization for virtual disks. Allaccess to the virtual disk is blocked during foreground initialization. Duringforeground initialization, zeros (0x00) are written to every sector of the virtualdisk. The virtual disk is available after foreground initialization is completed.Consistency CheckA consistency check verifies the correctness of data in a redundant array(RAID levels 1, 5, 6, and 10). For example, in a system with parity, checkingconsistency involves computing the data on one physical disk and comparingthe results to the contents of the parity physical disk.
