Best Practices for HP StorageWorks MSA2000 G1 or G2 and P2000

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Best Practices for HP StorageWorks MSA2000 G1 or G2 and P2000 | Manualzz

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You can designate a global spare to replace a failed drive in any virtual disk, or a vdisk spare to replace a failed drive in only a specific virtual disk. Alternatively, you can enable dynamic spares in

HP SMU. Dynamic sparing enables the system to use any drive that is not part of a virtual disk to replace a failed drive in any virtual disk.

Working with Failed Drives and Global Spares

When a failed drive rebuilds to a spare, the spare drive now becomes the new drive in the virtual disk. At this point, the original drive slot position that failed is no longer part of the virtual disk. The original drive now becomes a “Leftover” drive.

In order to get the original drive slot position to become part of the virtual disk again, do the following:

1.

2.

3.

4.

5.

6.

7.

Replace the failed drive with a new drive.

If the drive slot is still marked as “Leftover”, use the “Clear Disk Metadata” option found in the

“Tools” submenu.

When the new drive is online and marked as “Available”, configure the drive as a global spare drive.

Fail the drive in the original global spare location by removing it from the enclosure. The RAID engine will rebuild to the new global spare which will then become an active drive in the RAID set again.

Replace the drive you manually removed from the enclosure.

If the drive is marked as “Leftover”, clear the metadata as in step 2 above.

Re-configure the drive as the new global spare.

Tip:

A best practice is to designate a spare disk drive for use if a drive fails.

Although using a dedicated vdisk spare is the best way to provide spares for your virtual disks, it is also expensive to keep a spare assigned to each virtual disk. An alternative method is to enable dynamic spares or to assign one or more unused drives as global spares.

Cache configuration

Controller cache options can be set for individual volumes to improve a volume’s fault tolerance and

I/O performance.

Note:

To change the following cache settings, the user—who logs into the HP

SMU—must have the “advanced” user credential. The manage user has the

“standard” user credential by default. This credential can be changed using the HP SMU and click on “Configuration,” then “Users,” then “Modify Users.”

Write-back cache settings

Write back is a cache-writing strategy in which the controller receives the data to be written to disk, stores it in the memory buffer, and immediately sends the host operating system a signal that the write operation is complete, without waiting until the data is actually written to the disk drive. Write-back cache mirrors all of the data from one controller module cache to the other. Write-back cache improves the performance of write operations and the throughput of the controller.

When write-back cache is disabled, write-through becomes the cache-writing strategy. Using write-through cache, the controller writes the data to the disk before signaling the host operating system that the process is complete. Write-through cache has lower throughput and write operation performance than write back, but it is the safer strategy, with low risk of data loss on power failure.

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