Dell PowerVault MD3000 - Manual (Page 74)

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Troubleshooting Your Enclosure
Troubleshooting Enclosure Connections
Problem
• Enclosure is not seen by attached host controller.
Action
• Inspect RAID controller module cables for connectivity problems, such as damaged or disconnected
cables and poor connections. For detailed cabling instructions, see "Cabling Your RAID Enclosure" on
page 21.
Hard Controller Failures and Lockdown Conditions
Certain events can cause a RAID controller module to fail and/or shut down. Unrecoverable ECC
memory or PCI errors, or critical physical conditions can cause lockdown. If your RAID storage array is
configured for redundant access and cache mirroring, the surviving controller can normally recover
without data loss or shutdown.
Typical hard controller failures are detailed in the following sections.
Invalid Enclosure
The RAID controller module is supported only in a Dell-supported enclosure. Upon installation in the
enclosure, the controller performs a set of validation checks. The enclosure status LED is lit with a steady
blue color while the RAID controller module completes these initial tests and after the controller is
found to be working properly. If the RAID controller module detects a non-Dell supported enclosure, the
controller aborts startup. The RAID controller module will not generate any events to alert you in the
event of an invalid enclosure, but the enclosure status LED will blink amber to indicate a fault state.
For full details on the LEDs and their interpretation, see "Back-Panel Indicators and Features" on page 13.
ECC Errors
RAID controller firmware can detect ECC errors and can recover from a single-bit ECC error whether
the RAID controller module is in a redundant or nonredundant configuration. A storage array with
redundant controllers can recover from multi-bit ECC errors as well because the peer RAID controller
module can take over, if necessary.
The RAID controller module will failover if it experiences up to 10 single-bit errors, or up to three multi-
bit errors.
PCI Errors
The storage enclosure firmware can detect and only recover from PCI errors when the RAID controller
modules are configured for redundancy. If a virtual disk uses cache mirroring, it fails over to its peer
RAID controller module, which initiates a flush of the dirty cache.