•Stripe element size
•Read policy
•Write policy
•Type of initialization
•Hot spare configuration
NOTE: The default hard drive cache policy for a virtual disk with SAS hard drives is disabled and virtual disk with SATA hard drives is enabled. The Virtual Disk parameter cannot be changed in the BIOS Configuration Utility (<Ctrl> <R>). Use Dell OpenManage Storage Management for the hard drive cache setting operation.
The following table shows the parameters that you can configure when defining virtual disks.
Table 4. Parameters — description
Parameter | Description |
|
|
RAID Level | Specifies whether the virtual disk is RAID 0, 1, 5, 6, 10, 50, or 60. The number |
| of disks, disk capacity, requirements for fault tolerance, performance, and |
| capacity should be considered when selecting the RAID level. |
Stripe Element Size | Specifies the size of the segments written to each physical disk in a RAID 0, 1, |
| 5, 6, 10, 50, and 60 virtual disk. You can set the stripe element size to 64 KB |
| 128 KB, 256 KB, 512 KB, or 1 MB. The default and recommended stripe |
| element size is 64 KB. |
| A larger stripe element size provides better read performance if your system |
| mostly does sequential reads. |
Write Policy | Specifies the controller write policy. You can set the write policy to Write- |
| Back or |
| In |
| to the host when the controller cache has received all the data in a |
| transaction. |
| NOTE: If a Battery Backup Unit (BBU) is present, the default cache setting |
| is |
| setting is |
| NOTE: If |
| the controller may pause as the system flushes cache memory. |
| Controllers have a battery backup default to |
| In |
| completion signal to the host when the disk subsystem has received all |
| the data in a transaction. |
Read Policy | |
| the parameter to |
| The default is |
| |
| virtual disk. |
| ahead of requested data and store the additional data in the cache memory, |
| anticipating that the data is required soon. |
65