HP LC2000r HP NetRAID 1M/2M Installation & Configuration - Page 42

Chapter 4 Planning ◊ Although each drive in an array must have the same capacity, one logical drive can span two or more arrays with different capacities. For example, one array might contain three drives of 4 MB each, and the second array might contain three drives of 12 MB each. One logical drive can span both of these arrays. ◊ Spanned arrays must be numbered consecutively. ◊ When you use an HP NetRAID utility to configure your system, and you specify that a logical drive will span arrays, the system will span all eligible arrays that are numbered consecutively and that contain the same number of disk drives, up to a maximum of eight arrays. ◊ Spanned arrays must be controlled by the same adapter. Sample Worksheet B A sample Worksheet B is shown in Figure 4-4. The instructions for filling in each column are these: • For the Logical Drive # (column 1), use up to 40 logical drives, starting with LD0. • For the Array # (column 2), start with Array 0 and number consecutively. • In the Span column (3), you can choose to span this LD over the next 1-7 arrays. Enter your choice. • For the RAID Level (column 4), enter 0, 1, 5, 10, or 50 • The Logical Drive Size (column 5) is optional. You can let the HP NetRAID Assistant Wizard calculate the size. • The Stripe Size (column 6) can be 2, 4, 8, 16, 32, 64, or 128 KB. • The Write Policy (column 7) is either Write Back or Write Thru. • The Read Policy (column 8) can be Normal, Read Ahead, or Adaptive Read Ahead. • The Cache Policy (column 9) can be Cached I/O or Direct I/O. 34