HP Dc5750 WebPAM User Manual - Page 106

WebPAM User Manual The Expansion feature applies only to RAID 0 and RAID 5 arrays. You can add physical drives as described in the table below. From RAID 0: 1 drive RAID 0: 2 drives RAID 0: 3 drives RAID 5: 3 drives To Result RAID 0: 2, 3 or 4 drives Increased capacity RAID 0: 3 or 4 drives Increased capacity RAID 0: 4 drives Increased capacity RAID 5: 4 drives Increased capacity Important • The Target logical drive may require more disk drives than the Source logical drive • If the Target logical drive requires an EVEN number of disk drives but the Source logical drive has an ODD number, ADD a disk drive as part of the migration process • You cannot reduce the number of disk drives in your logical drive • You cannot migrate or expand a logical drive when it is Critical or performing activities such as Synchronizing or Rebuilding Ranges of Logical Drive Expansion There are limitations to how large you can expand a logical drive, depending on the size of your current logical drive. The current PC Operating Systems support a 10-byte LBA format. This means that a logical drive can have up to 4 billion address blocks or sectors. Multiply the number of blocks by the sector size to find the capacity of a logical drive: 4,000,000,000 blocks x 512 bytes per sector = 2,048,000,000,000 bytes of data for a 2TB drive. Note that you cannot change the size of the sectors nor can you increase the number of address blocks above 4 billiion. As a result, there are range limits imposed upon logical drive expansion as shown in the table above. For example: • You can expand a 2.5 TB logical drive up to 4 TB • You can only expand a 1.9 TB logical drive up to 2 TB 100