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Troubleshooting
To get help with your Dell Shared PowerEdge RAID Controller Shared (PERC) 8 card, you can contact
your Dell Technical Service representative or see dell.com/contactdell.
Performance variations between write-back and write-
through cache modes
Performance is highly variable across configurations, drive type, applications and IO workloads. The write
performance of write-through mode is typically lower than that of write-back mode. Some
configurations and workloads exhibit significant performance deltas.
Evaluate your needs for maximum I/O performance (a single Shared PERC 8 configuration) versus
maximum data protection (a Fault Tolerant Shared PERC 8 configuration).
Shared PERC 8 Card Boots Into Safe Mode
In the event of some failure conditions encountered at boot, Shared PERC 8 boots with restricted
capability in safe mode without user intervention. In such a condition Shared PERC 8 reports all
configured disk drives as Foreign to the management application. The Dell Chassis Management
Controller (CMC) displays events generated by the Shared PERC 8 card indicating the reason for booting
into safe mode. The following table details the conditions and the corresponding event notifications that
are reported to the CMC.
Table 2. Conditions and the Corresponding Event Notifications Reported to the CMC
Category Event Reported To the CMC Description of the
Failure
Corrective Action
Pinned
Cache
Controller cache pinned
for missing or offline
VDs: %s
The Shared PERC 8 card
preserves dirty cache for
a virtual disk that
transitioned to offline or
was deleted due to
missing physical disks.
You can restore the
preserved cache to the
virtual disk once the
original drives are re-
inserted and the foreign
configuration is imported.
SAS
Discovery
Controller booted to safe
mode due to critical
errors Critical Error
during boot - On-board
expander FW or mfg image
is corrupted - reflash
image
This issue occurs if
expanders are not
detected.
Reseat and cable the
expanders.
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