HP StorageWorks 500 G2 Modular Smart Array - Manual (Page 79)

Troubleshooting 79
• ADU lists all failed drives.
• CPQONLIN identifies failed drives in a NetWare environment.
For additional information about diagnosing hard drive problems, refer to the HP
ProLiant Servers Troubleshooting Guide.
CAUTION: Sometimes, a drive that has previously been failed
by the controller may seem to be operational after the system is power-
cycled or (for a hot-pluggable drive) after the drive has been removed
and reinserted. However, continued use of such marginal drives may
eventually result in data loss. Replace the marginal drive as soon as
possible.
Effects of a hard drive failure
When a hard drive fails, all logical drives that are in the same array are affected.
Each logical drive in an array may be using a different fault-tolerance method, so
each logical drive can be affected differently.
• RAID 0 configurations cannot tolerate drive failure. If any physical drive in
the array fails, all non-fault-tolerant (RAID 0) logical drives in the same
array will also fail.
• RAID 1+0 configurations can tolerate multiple drive failures as long as no
failed drives are mirrored to one another.
• RAID 5 configurations can tolerate one drive failure.
• RAID ADG configurations can tolerate simultaneous failure of two drives.
Compromised fault tolerance
If more hard drives fail than the fault-tolerance method allows, fault tolerance is
compromised, and the logical drive fails. In this case, all requests from the
operating system are rejected with unrecoverable errors. You are likely to lose
data, although it can sometimes be recovered.