HP 166207-B21 Smart Array 5300 Controller User Guide - Page 67

Migrating RAID Level or Stripe Size

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Configuring an Array 8. Make the extra capacity of the logical drive available to the operating system by one of the following methods: - Create a new partition in the logical drive by using the operating system partitioning software. - Increase the size of an existing partition by using the operating system partitioning software or third-party partitioning tools. Migrating RAID Level or Stripe Size NOTE: Before migrating the stripe size, check that the memory available to the array accelerator is no smaller than the lowest common multiple of the total stripe sizes of the two different configurations. For example, consider the change from an 11-drive RAID 5 logical volume to a 14-drive RAID 1+0 logical volume. If each configuration uses the corresponding default stripe width, the block size changes from 16 kbytes per stripe to 128 kbytes per stripe. • A full stripe in the RAID 5 configuration contains 160 kbytes (ten of the drives contain user data; one drive contains parity data). • A full stripe in the RAID 1+0 configuration contains 896 kbytes. The lowest common multiple of the two stripe sizes is 4480 kbytes, and this figure represents the minimum amount of memory that must be available to the array accelerator. To migrate to a different RAID level or stripe size: 1. Back up all data on the logical drive. Although migration is unlikely to cause data loss, observing this precaution provides extra security. The backup data may also be needed if the number of sectors needs to be increased (this fact will be determined in step 8). 2. Check that the array accelerator batteries (if present) are fully charged. NOTE: The migration process takes about 15 minutes per gigabyte. Data can still be read from or written to any logical drive on the controller during a migration, although performance might be reduced. However, a controller can perform only one expansion, extension, or migration at any given time. 3. If your controller has a battery-backed write cache, check the Controller Settings screen in ACU to confirm that the write cache is enabled. 4. Select the logical drive in the Logical Configuration View window. Compaq Smart Array 5300 Controller User Guide 7-25

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Configuring an Array
Compaq Smart Array 5300 Controller User Guide
7-25
8.
Make the extra capacity of the logical drive available to the operating system by
one of the following methods:
—
Create a new partition in the logical drive by using the operating system
partitioning software.
—
Increase the size of an existing partition by using the operating system
partitioning software or third-party partitioning tools.
Migrating RAID Level or Stripe Size
NOTE:
Before migrating the stripe size, check that the memory available to the array
accelerator is no smaller than the lowest common multiple of the total stripe sizes of the two
different configurations.
For example, consider the change from an 11-drive RAID 5 logical volume to a 14-drive
RAID 1+0 logical volume. If each configuration uses the corresponding default stripe width, the
block size changes from 16 kbytes per stripe to 128 kbytes per stripe.
•
A full stripe in the RAID 5 configuration contains 160 kbytes (ten of the drives contain user
data; one drive contains parity data).
•
A full stripe in the RAID 1+0 configuration contains 896 kbytes.
The lowest common multiple of the two stripe sizes is 4480 kbytes, and this figure represents
the minimum amount of memory that must be available to the array accelerator.
To migrate to a different RAID level or stripe size:
1.
Back up all data on the logical drive. Although migration is unlikely to cause
data loss, observing this precaution provides extra security. The backup data may
also be needed if the number of sectors needs to be increased (this fact will be
determined in step 8).
2.
Check that the array accelerator batteries (if present) are fully charged.
NOTE:
The migration process takes about 15 minutes per gigabyte. Data can still be read
from or written to any logical drive on the controller during a migration, although
performance might be reduced. However, a controller can perform only one expansion,
extension, or migration at any given time.
3.
If your controller has a battery-backed write cache, check the
Controller
Settings
screen in ACU to confirm that the write cache is enabled.
4.
Select the logical drive in the
Logical Configuration View
window.