User guide

Chapter 9. Maintaining Units
148 3ware Serial ATA RAID Controller User Guide
How Errors Are Handled
Verification makes use of the same error checking and error repair techniques
used during ordinary use of drives configured through 3ware RAID
controllers.
When verification encounters an error, the controller typically retries the
command. If there are cable CRC errors, there may be multiple retries
including downgrade of the UDMA mode. If the error persists and is
unrepairable (e.g., ECC errors), an error notification is issued to indicate the
problem. (See AEN “0026 Drive ECC error reported” on page 239.)
If the disk drive is part of a redundant unit that is in a redundant state (not
degraded or rebuilding), then Dynamic Sector Repair automatically rewrites
the redundant data to the error location to force the drive to reallocate the
error location. A notification of repair is posted to the alarms list. The result is
a restoration of drive and data integrity; the primary and redundant data are
again both valid.
If the unit is not redundant, it is recommended that you perform a file-system
check to correct the issue. Under Windows, you can do this by right-clicking
on the Drive and choosing Properties; then on the Tools tab, click Check Now.
If the errors persist and cannot be overwritten from a backup copy, perform a
final backup of files that have changed since your last backup. You will need
to replace the defective drive, recreate the array, and reinstall the data.
Starting a Verify Manually
Verification of units can be done automatically, on a schedule, or can be
started manually, as described below. (See “Setting Auto Verify for a Unit” on
page 109 and “Scheduling Background Tasks” on page 156.)
You can manually start a verify through either 3DM or 3BM.
Note: If the unit has not previously been initialized and you manually select Verify
Unit
in either 3BM or 3DM, the initialization process starts.