Dell PowerVault MD3260i - Manual (Page 115)

The test results contain a generic, overall status message and a set of specific test results. Each test result contains the
following information:
• Test (read/write/data loopback)
• Port (read/write)
• Level (internal/external)
• Status (pass/fail)
Events are written to the MEL when diagnostics are started and when testing is completed. These events help you to
evaluate whether diagnostics testing was successful or failed and the reason for the failure.
Recovery Operations
Recovery operations involve replacing failed RAID controller modules and physical disks, restoring data, and restoring
the storage array to operation.
Setting RAID Controller Module Operational Mode
A RAID controller module has three operational modes:
• Online
• Offline
• Service
CAUTION: Placing a RAID controller module offline can cause loss of data.
Placing a RAID controller module online sets it to the Optimal state and makes it active and available for I/O operations.
Placing a RAID controller module offline makes it unavailable for I/O operations and moves its disk groups to the other
RAID controller module if failover protection is enabled.
Taking a RAID controller module offline can seriously impact data integrity and storage array operation.
If you take a RAID controller module offline, the second RAID controller module in the pair takes over. Disk groups and
their associated virtual disks that were assigned to the offline RAID controller module are automatically reassigned to
the remaining RAID controller module.
CAUTION: Place a RAID controller module in Service mode only under the direction of Technical Support.
Use Service mode when you want to perform an operation, such as replacing a RAID controller module. Placing a RAID
controller module in Service mode makes it unavailable for I/O operations. Placing a RAID controller module in Service
mode also moves the disk groups from the RAID controller module to the second RAID controller module without
affecting the disk groups’ preferred path. Moving disk groups might significantly reduce performance. The disk groups
are automatically transferred back to the preferred RAID controller module when it is placed back online.
CAUTION: A multipath driver is required on all hosts and is the only supported configuration. If the multipath driver
is not installed, the virtual disks are not accessible.
Before you place a RAID controller module in Service mode, ensure that a multipath driver is installed on all hosts using
these virtual disks.
To change the operational mode of a RAID controller module, run the following command:
set controller [(0 | 1)] availability=(online | offline | serviceMode)
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