User manual

prediCtive dAtA migrAtion (pdm)
PDM is the migration of data from a suspect drive (a drive with bad
sectors) to a spare drive. Unlike Rebuilding, PDM constantly monitors
drives and automatically copies data to a spare drive before the
suspect drive fails and the logical drive goes Critical. PDM also counts
the number of media errors reported by Media Patrol. The following
actions trigger PDM:
• A hard drive is detected with unhealthy status, such as when a
SMART error is reported or the bad sector remapping table fills to
the specified level
• Media Patrol finds a disk critical error
• You initiate PDM manually
You can specify maximum levels for reassigned and error blocks in
PDM settings. When the table fills to a specified value, PDM triggers a
data migration from the suspect drive to a replacement physical drive.
Logical drives are accessible during data migration, but they respond
more slowly to read/write tasks. The time required for data migration
depends on the size of the hard drives. PDM is enabled on all disk
arrays by default. Disabling PDM is possible but not recommended.
trAnSition
Transition is the process of replacing a revertible spare drive that is
currently part of a disk array with an unconfigured physical drive or a
non-revertible spare. The revertible spare drive returns to its original
status. In order to run the Transition function, the spare drive must be
revertible. In addition, you must specify an unconfigured physical drive
of the same or larger capacity and same media type as the revertible
spare drive.
SynCHronizAtion
Synchronization recalculates the redundancy data to ensure that the working
data on the physical drives is properly in sync. To see whether a drive has been
synchronized, follow these steps:
1. From the Administration tab, click the Background Activity menu item.
2. Move your pointer over the Synchronization row and click on the View
button for a logical drive.
3. Look under Logical Drive Information beside the line that says
Synchronized. “Yes” means the logical drive was synchronized.
To change Synchronization settings, follow these steps:
1. From the Administration tab, click the Background Activity menu item.
2. Click the Settings button.
3. Click the Background Synchronization Rate drop-down menu and choose
a rate:
• Low—Fewer system resources to Synchronization, more to data read/
write operations.
• Medium—Balances system resources between Synchronization and data
read/write operations.
• High—More system resources to Synchronization, fewer to data read/write
operations.
4. Click the Confirm button.
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