HP Smart Array Cluster Storage System

Troubleshooting
D-6 HP Smart Array Cluster Storage System User Guide
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Writer: Rob Weaver File Name: j-appd Troubleshooting
Codename: Aurora Part Number: 240333-003 Last Saved On: 11/6/02 1:07 PM
Recovering from Hard Drive Failure
CAUTION: Back up all data before removing drives or changing configurations.
Failure to do so could result in permanent loss of data. Before moving drives and
arrays, run ACU 6.0.
The purpose of fault-tolerant configurations on the HP Smart Array Cluster Storage
Controller is to protect against data loss due to drive failure. Although the Smart
Array Cluster Storage controller firmware is designed to protect against normal drive
failure, you must perform the correct actions to recover from a drive failure without
inadvertently inducing any additional drive failures. Multiple drive failures in the
same array generally result in data loss (exceptions include failures following
activation of a spare drive, and failure of drives in a mirroring configuration that are
not mirrored to one another or ADG configuration).
Drives may be either Ultra2 or Ultra 3 hot-plug universal hard disk drives. When
grouping drives in an array, always use drives of the same capacity. The array cannot
use the excess capacity of a larger drive, so this capacity is ignored and wasted.
A list of supported hard drives is available at the HP website
www.hp.com/products/sharedstorage
Hard Drive Failure
When a hard drive fails, all logical drives in the same array are affected. Each logical
drive in an array may be using a different fault tolerance method, so the effect on
each logical drive can be different.
• RAID 0 configurations cannot tolerate drive failure. If any physical drive in the
array fails, the controller fails all non-fault-tolerant (RAID 0) logical drives in the
same array.
• RAID 1 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 in the
array.