Consistency Check; Copyback - Lenovo ThinkServer RD240 Software User's Manual

2.4.5

Consistency Check

2.4.6

Copyback

not stop. The controller uses different paths to balance the load on the
entire system.
In the MegaRAID Storage Manager utility, when multiple paths are
available to a drive, the drive information will show only one enclosure.
The utility shows that a redundant path is available to a drive. All drives
with a redundant path display this information. The firmware supports
online replacement of enclosure modules.
The Consistency Check operation verifies correctness of the data in
virtual drives that use RAID levels 1, 5, 6, 10, 50, and 60. (RAID 0 does
not provide data redundancy). For example, in a system with parity,
checking consistency means computing the data on one drive and
comparing the results to the contents of the parity drive.
Note: It is recommended that you perform a consistency check at
least once a month.
The copyback feature allows you to copy data from a source drive of a
virtual drive to a destination drive that is not a part of the virtual drive.
Copyback is often used to create or restore a specific physical
configuration for a drive group (for example, a specific arrangement of
drive group members on the device I/O buses). Copyback can be run
automatically or manually.
Typically, when a drive fails or is expected to fail, the data is rebuilt on a
hot spare. The failed drive is replaced with a new disk. Then the data is
copied from the hot spare to the new drive, and the hot spare reverts
from a rebuild drive to its original hot spare status. The copyback
operation runs as a background activity, and the virtual drive is still
available online to the host.
Copyback is also initiated when the first Self-Monitoring Analysis and
Reporting Technology (SMART) error occurs on a drive that is part of a
virtual drive. The destination drive is a hot spare that qualifies as a
rebuild drive. The drive with the SMART error is marked as "failed" only
after the successful completion of the copyback. This avoids putting the
drive group in degraded status.
Components and Features 2-5