HP 5300 - Manual (Page 63)

Configuring an Array
HP Smart Array 5300 Controller User Guide 7-21
HP CONFIDENTIAL
Writer: Jennifer Hayward File Name: h-ch7 configuring an array
Codename: SilverHammer Part Number: 135606-005 Last Saved On: 10/8/02 11:15 AM
During capacity expansion, ACU automatically redistributes existing logical drives
across all of the physical drives in the expanded array. If the array being expanded
has more than one logical drive, data is redistributed one logical drive at a time.
Newly created logical drives are not available until capacity expansion has finished.
CAUTION: Do not exchange the controller or array accelerator board during array
capacity expansion. Interrupting expansion in this way causes irretrievable data loss.
NOTE: The expansion process takes about 15 minutes per gigabyte. Data can still be read
from or written to any logical drive on the controller during an expansion, although
performance might be reduced. However, a controller can perform only one expansion,
extension, or migration at any given time.
There are three stages in the procedure for expanding an array:
1. Back up all data on the array. Although array expansion is unlikely to cause data
loss, observing this precaution will provide additional data protection.
2. Install the new physical drives. The capacity of each new drive must be no less
than that of the drives that are currently in the array.
IMPORTANT: Do not assign a group of physical drives to the same array unless they are
of the same capacity. If the drives have different capacities, the excess capacity of the
larger drives cannot be used by the array and is wasted.
3. Assign the new physical drives to an existing array. When the expansion process
is complete, the extra capacity can be used to increase the size of an existing
logical drive (refer to the “Extending Logical Drive Capacity” section) or to
create a new logical drive.
For example, consider a controller with the two arrays that were made in the example
given in the “Creating a New Array” section:
• Array A—seven 9.1-GB drives in a RAID 5 configuration with a spare
• Array B—two 9.1-GB drives in a RAID 1+0 configuration without a spare