HP StorageWorks P2000 HP StorageWorks P2000 G3 MSA System FC/iSCSI User Guide - Page 21

Transportable CompactFlash, Super-capacitor pack

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cached data, the controller immediately loads the data into the system memory, avoiding the latency of a disk access. NOTE: See HP StorageWorks P2000 G3 MSA System SMU Reference Guide for more information about volume cache options. Transportable CompactFlash During a power loss or array controller failure, data stored in cache are saved off to non-volatile memory (CompactFlash). These data are then written to disk after the issue is corrected. To protect against writing incomplete data to disk, the image stored on the CompactFlash is verified before committing to disk. In single-controller configurations, if the controller has failed or does not start, and the Cache Status LED is on or blinking, the CompactFlash will need to be transported to a replacement controller to recover data not flushed to disk. (See Controller failure in a single-controller configuration on page 54 for more information.) Controller Module CompactFlash CAUTION: To preserve the existing data stored in the CompactFlash, you must transport the CompactfFlash from the failed controller to the replacement controller using a procedure outlined in the HP StorageWorks Controller Module Replacement Instructions, shipped with the replacement controller. Failure to use this procedure will result in the loss of data stored in the cache module. The CompactFlash must stay with the same enclosure. If the CompactFlash is used/installed in a different enclosure, data loss/data corruption will occur. IMPORTANT: In dual controller configurations, there is no need to transport a failed controller's cache to a replacement controller because the cache is duplicated between the controllers. Super-capacitor pack To protect RAID controller cache in case of power failure, P2000 G3 MSA System controllers are equipped with super-capacitor technology, in conjunction with CompactFlash memory, built into each controller module to provide unlimited cache memory backup time. The super-capacitor pack provides energy for backing up unwritten data in the write cache to the CompactFlash in the event of a power failure. Unwritten data in CompactFlash memory is automatically committed to disk media when power is restored. While the cache is being maintained by the super-capacitor, the Cache Status LED flashes at a rate of 1/10 second on and 9/10 second off. HP StorageWorks P2000 G3 MSA System FC/iSCSI User Guide 21

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HP StorageWorks P2000 G3 MSA System FC/iSCSI User Guide
21
cached data, the controller immediately loads the data into the system memory, avoiding the latency of
a disk access.
NOTE:
See
HP StorageWorks P2000 G3 MSA System SMU Reference Guide
for more information about
volume cache options.
Transportable CompactFlash
During a power loss or array controller failure, data stored in cache are saved off to non-volatile memory
(CompactFlash). These data are then written to disk after the issue is corrected. To protect against writing
incomplete data to disk, the image stored on the CompactFlash is verified before committing to disk.
In single-controller configurations, if the controller has failed or does not start, and the Cache Status LED is
on or blinking, the CompactFlash will need to be transported to a replacement controller to recover data
not flushed to disk. (See
Controller failure in a single-controller configuration
on page 54 for more
information.)
CAUTION:
To preserve the existing data stored in the CompactFlash, you must transport the
CompactfFlash from the failed controller to the replacement controller using a procedure outlined in the
HP
StorageWorks Controller Module Replacement Instructions
, shipped with the replacement controller. Failure
to use this procedure will result in the loss of data stored in the cache module. The CompactFlash must stay
with the same enclosure. If the CompactFlash is used/installed in a different enclosure, data loss/data
corruption will occur.
IMPORTANT:
In dual controller configurations, there is no need to transport a failed controller’s cache to
a replacement controller because the cache is duplicated between the controllers.
Super-capacitor pack
To protect RAID controller cache in case of power failure, P2000 G3 MSA System controllers are equipped
with super-capacitor technology, in conjunction with CompactFlash memory, built into each controller
module to provide unlimited cache memory backup time. The super-capacitor pack provides energy for
backing up unwritten data in the write cache to the CompactFlash in the event of a power failure. Unwritten
data in CompactFlash memory is automatically committed to disk media when power is restored. While
the cache is being maintained by the super-capacitor, the Cache Status LED flashes at a rate of 1/10
second on and 9/10 second off.
Controller Module
CompactFlash