CLI Guide

trust
Description Enables an offline disk group to be brought online for emergency data recovery.
CAUTION: Improper use of trust may cause data corruption or data loss.
NOTE: This command is for use by or with direction from technical support.
This command must be enabled before each use. If used improperly this command can cause unstable
operation and data loss. Before use, carefully read the cautions and procedures below.
The trust command provides an opportunity to recover data from a disk group that has failed due to disk
failure. The command forces a resynchronization of the metadata (as well as time and date stamps) that
unifies members of a disk group, and essentially puts the disk group back into an accessible state. As long as
the failed disks are operable, data can be read from the disks and restored to another location.
From examining the state of the disks, if the command determines that the trust operation is unsafe—that it
may result in an unstable disk group with data corruption—the command will fail. You may then seek
assistance from technical support or run the command with a special parameter to acknowledge the risk of
proceeding. Otherwise, if the command determines the operation to be safe, the command will proceed.
When the “trusted” disk group is back online, back up its data and audit the data to make sure that it is intact.
Then delete that disk group, create a new disk group, and restore data from the backup to the new disk
group. Using a trusted disk group is only a disaster-recovery measure. The disk group has no tolerance for
any additional failures.
The following procedure outlines the general steps for performing a trust operation, but the best procedure
to follow for your situation may vary from this procedure. Before starting this procedure, contact technical
support for assistance in determining if the trust operation applies to your situation, and for assistance to
perform it.
CAUTION:
1. Do not use the trust command when the storage system is unstable. For example, if there
are many power or topology-change events.
2. The trust command can be run on a quarantined-offline or offline disk group. In many cases
the disk group will be automatically dequarantined. If you cannot resolve the issue that
caused the disk to become quarantined such that it is automatically dequarantined, and if
the trust operation is applicable to your situation, then proceed to trust.
NOTE: The best practice is to dequarantine the disk group and then proceed to trust
the offline disk group. If the dequarantine command fails then contact technical
support for assistance.
CAUTION: Performing trust on a quarantined-offline disk group can cause data
corruption because it will bring a disk with stale data back into the disk group.
3. Never update controller-module, expansion-module, or disk firmware when the disk group
is offline.
4. Never clear unwritten data cache when a disk group is offline.
5. Do not use the trust command on a disk group that failed during disk-group expansion.
6. Do not use the trust command on a disk group with status CRIT. Instead, add spares and
let the system reconstruct the disk group.
The trust command must be used in CLI console mode.Steps for running the trust command:
1. Disable background scrub of disks and disk group to avoid running scrubs automatically.
2. Identify the cause for the disk group becoming offline.
3. If an external issue (power, cabling, and so forth) caused the disk group to fail, fix the external issue
before continuing to the next step.
4. Disable host access to the failed disk group. In a single-controller configuration, disconnect the host-port
cables. In a dual-controller configuration:
a. Determine the owning controller of the failed disk group.
b. As a precautionary measure, remove the host-port cables of the owning controller of the offline disk
grou.p
Alphabetical list of commands
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