IBM ServeRAID-8 Series, Лучшие практики и информация по обслуживанию

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Correct mounting of the ServeRAID-8k RAID enabler battery
Mount the ServeRAID-8k battery to the system chassis. If the battery is mounted to
the ServeRAID-8k RAID enabler card, the weight of the battery on such a small
component, combined with runtime vibration and heat, can damage the enabler
card, which results in an offline array and possibly loss of data.
Figure 8 shows the correct battery mounting.
Physical drives are online, but the logical drive is offline
In rare catastrophic failures, the controller might not be able to recover the logical
drive. The failure results in the symptom where the physical drives appear online
while the logical drives remain offline and inaccessible. This is caused by two nearly
simultaneous failures within the subsystem. When the first drive goes offline, the
controller begins writing a new age count and deadmap value to the metadata of
the surviving member drives of the array. Unfortunately, if the second drive fails
almost simultaneously, the controller immediately stops all metadata updates, and in
this special case, the controller completes only partial updates to the surviving
member drives. When the controller restarts, it reads two sets of metadata. The first
set has a newer age count, and the second has an older age count. The controller
does not know which metadata to trust, so it keeps the array offline.
The Force Online option has some limitations. Ideally, the Force Online option
forces the age count to the next common number and sets the deadmap value to 0.
This does not mean that the data is good if the force online is successful. The
following criteria must be true for the Force Online option to work:
v The logical volume is offline.
v
All the members (physical disks) of the array are present.
Figure 8. Correct battery mounting of a ServeRAID-8k battery
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ServeRAID-8 Series: Best Practices and Maintenance Information