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For additional information about diagnosing disk drive problems, see the troubleshooting guide for the applicable
generation of ProLiant server (for example, Gen9 or Gen10) on the Hewlett Packard Enterprise Support Center
website.
CAUTION: Sometimes, a drive that has previously failed 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 drive as soon as possible.
Understanding the effects of a hard drive failure
If 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 a 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
(with no spares assigned).
•
RAID 5 configurations can tolerate one drive failure (with no spares assigned).
•
RAID 6 with ADG configurations can tolerate simultaneous failure of two drives (with no spares assigned).
Identifying a compromised fault tolerance
CAUTION: If fault tolerance is compromised, data loss can occur. However, it may be possible to recover the data.
For more information, see Recovering from compromised fault tolerance.
If more drives fail than the fault-tolerance method can manage, fault tolerance is compromised, and the logical drive fails.
If this failure occurs, the operating system rejects all requests and indicates unrecoverable errors.
For example, fault tolerance might occur when a drive in an array fails while another drive in the array is being rebuilt.
Compromised fault tolerance can also be caused by problems unrelated to drives. In such cases, replacing the physical
drives is not required.
Recovering from compromised fault tolerance
If fault tolerance is compromised, inserting replacement drives does not improve the condition of the logical volume.
Perform the following procedure to recover data:
1. Check for loose, dirty, broken, or bent cabling and connectors on all devices.
2. Power down the D6020 (see Powering down the D6020).
3. Power up the D6020 (see Powering up the D6020).
In some cases, a marginal drive is operational long enough to allow backup of important files.
4. Make copies of important data, if possible.
5. Replace any failed drives.
Disk drive replacement guidelines
You can replace disk drives without powering down the system. However, before replacing a degraded drive:
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Troubleshooting
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