Users Guide

• Default — The disk uses the default write cache mode.
• Enabled — Disk Cache Policy is enabled.
• Disabled — Disk Cache Policy is disabled.
• Inconsistent — The disk cache policy is not uniform across all the physical disks in the virtual disk. For example, if a virtual disk
contains three physical disks; the disk cache policy of the rst physical disk is Enabled, the second physical disk is Disabled, and the
third physical disk is Default. Then the disk cache policy state for the virtual disk is displayed as Inconsistent.
NOTE: The default setting for Disk Cache Policy for virtual disks based on SATA drives is Enabled, and for virtual disks based on
SAS drives is Disabled.
NOTE: For SAS 6i/R and PERC H200 family of controllers, the Disk Cache Policy setting is available only after creating the
virtual disk.
Related Task
• Changing The Virtual Disk Policy
Background Initialization On PERC Controllers
On PERC controllers, background initialization of a redundant virtual disk begins automatically within 0 to 5 minutes after the virtual disk is
created. The background initialization of a redundant virtual disk prepares the virtual disk to maintain redundant data and improve write
performance. For example, after the background initialization of a RAID 5 virtual disk completes, the parity information is initialized. After
the background initialization of a RAID 1 virtual disk completes, the physical disks are mirrored.
The background initialization process helps the controller identify and correct problems that may occur with the redundant data later. In this
regard, the background initialization process is similar to a check consistency.
The background initialization should be allowed to run to completion. If canceled, the background initialization automatically restarts within
0 to 5 minutes. Some processes such as read and write operations are possible while the background initialization is running. However,
other processes such as creating a virtual disk, cannot be run concurrently with background initialization. These processes cause the
background initialization to cancel.
Non-RAID Controller Description
The non-RAID SCSI and SAS controllers are non-RAID controllers that support SCSI and SAS devices. Because these controllers are non-
RAID, they do not support virtual disks. You can manage these non-RAID controllers and their attached SCSI and SAS devices with Storage
Management.
NOTE
: Supported features may vary from controller to controller.
Non-RAID SAS Controllers
The following non-RAID controllers use Serial Attached SCSI (SAS) technology:
• HBA 330 MX
• HBA 330 MMZ
• SAS 6 Gbps Host Bus Adapter (HBA)
• Broadcom SAS 9207-8e
• Broadcom SAS 9300-8e
• Broadcom SAS 9206-16e
• SAS 12 Gbps HBA
• HBA 330 Mini
• HBA 330 Adapter
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Controllers