Media Patrol; Predictive Data Migration (Pdm); Pdm Triggers - Promise VTRAK M610i Product Manual

VTrak M610i, M310i, M210i Product Manual

Media Patrol

Media Patrol is a routine maintenance procedure that checks the magnetic media
on each disk drive. Media Patrol checks all physical drives assigned to disk
arrays. Media Patrol does not check unconfigured drives.
Media Patrol will also check spare drives, if those drives have Media Patrol
enabled. Media Patrol for spare drives is enabled by default. You can disable it in
VTrak's Command Line Interface (CLI).
Unlike Synchronization and Redundancy Check, Media Patrol is concerned with
the condition of the media itself, not the data recorded on the media. If Media
Patrol encounters a critical error, it triggers PDM if PDM is enabled.
You can run Media Patrol from the subsystem. See "Running Media Patrol" on
page 52 (WebPAM PROe) or page 136 (CLU).
You can also run Media Patrol on a disk array in WebPAM PROe. See page 115.

Predictive Data Migration (PDM)

Predictive Data Migration (PDM) is the migration of data from the suspect disk
drive to a spare disk drive, similar to Rebuilding a Logical Drive. But unlike
Rebuilding, PDM constantly monitors your disk drives and automatically copies
your data to a spare disk drive before the disk drive fails and your Logical Drive
goes Critical. See "Running PDM" on page 52 (WebPAM PROe) or page 155
(CLU).
After the data is copied from the suspect disk drive, the controller marks it with a
Stale configuration and a PFA error.
You can clear the Stale configuration and PFA error and put the disk drive back
into service. See "Clearing Stale and PFA Conditions" on page 102 (WebPAM
PROe) or page 145 (CLU). In some cases, however, you might remove the disk
drive for repair or replacement.

PDM Triggers

The following actions trigger PDM:
• A disk drive with unhealthy status (see below)
• Media Patrol finds a disk critical error*
• You initiate PDM manually
*PDM also counts the number of media errors reported by Media Patrol.
A disk drive becomes unhealthy when:
• A SMART error is reported
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