Users Guide

Degraded State Of Virtual Disks

A redundant virtual disk is in a degraded state when one or more physical disks have failed or are

inaccessible. For example, if a RAID 1 virtual disk consists of two physical disks and one of them fails or

become inaccessible, the virtual disk become degraded.

To recover a virtual disk from a degraded state, you must replace the failed physical disk and rebuild it.

Once the rebuilding process is complete, the virtual disk state changes from degraded to optimal. For

information on rebuilding the disk, see the topic Performing A Manual Rebuild Of An Individual Physical

Disk.

Memory errors

Memory errors can corrupt cached data, so the controllers are designed to detect and attempt to recover

from the memory errors. Single-bit memory errors can be handled by the controller and do not disrupt

normal operation. A notification is sent if the number of single-bit errors exceeds a threshold value.

Multi-bit errors are more serious as they result in corrupted data and data loss. The following are the

actions that occur in the case of multi-bit errors:

• If a multi-bit error occurs while accessing data in the cache when the controller is started with dirty

cache, the controller discards the cache contents. The controller generates a warning message to the

system console to indicate that the cache was discarded and generates an event.

• If a multi-bit error occurs at run-time either in code/data or in the cache, the controller stops.

• The controller logs an event to the controller’s internal event log and a message during POST is

displayed indicating a multi-bit error has occurred.

NOTE: In case of a multi-bit error, contact Dell Technical Support.

Preserved Cache State

The controller preserves the dirty cache from a virtual disk if the virtual disk becomes offline or is deleted

because of missing physical disks. This preserved dirty cache is called pinned cache and is preserved until

you import the virtual disk or discard the cache.

Use the BIOS Configuration Utility (<Ctrl> <R>) to select whether to import the virtual disk or discard the

preserved cache. In the VD Mgmt menu, select Manage Preserved Cache and follow the steps on the

screen.

General issues

PERC Card Has Yellow Bang In Device Manager

Issue: The device is displayed in Device Manager but has a yellow bang (exclamation

mark).

Corrective Action: Reinstall the driver. For more information on reinstalling drivers, see the topic

Driver Installation.