Dell PowerEdge RAID Controller S110 - Manual (Page 18)

16 Features
CAUTION: The BIOS Configuration Utility (<CTRL><R>) pauses, and prompts for
action, for the degraded virtual disk(s), if a "pause if degraded" option is enabled
in the BIOS Configuration Utility (<CTRL><R>).
CAUTION: After the migration occurs, make sure that all of the physical disks
have been migrated and are present in the appropriate virtual disks.
Virtual Disk RAID Levels
Virtual disks can be created at different RAID levels.
Virtual Disk Transformation
Virtual disk transformation can consist of:
• Capacity expansion, using OCE/Reconfigure (to allocate additional virtual
disk space on the original physical disks or after additional physical disks
are added).
• Rebuilding (rebuilding data on a virtual disk consists of using an available
hot spare or backup physical disk).
Read, Write, and Cache Policy
Table 2-1 indicates the read, write, and cache policies that are supported by
the PERC S110 adapter.
CAUTION: The current default for Write-Cache mode enablement is
Write Through, No Read Ahead (WT, NRA). To enable Write Back (WB), a UPS is
recommended.
Table 2-1. Read, Write, and Cache Policy for the PERC S110
Category Supported by PERC S110 adapter
Cache Settings Yes
Read Ahead/Write Back Yes
No Read Ahead/Write Back Yes
Read Ahead/Write Through Yes
No Read Ahead/Write Through Yes
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