Raid Group Media Maintenance; Media Scan Options; Start A Manual Media Scan; Schedule A Media Scan - Sonnet Fusion RAID Storage Systems Operation Manual

1.7 RAID Group Media Maintenance

The Media Scan feature scans disk drives for media errors and parity
errors. All media errors are counted and fixed. All parity errors are
reported in the event log. The two options are described below.
Use the ATTO Configuration Tool to check and repair media
errors on parity RAID groups. You may start the media scan
operations manually, or schedule the operations for a later time,
or on a weekly basis.

Media Scan Options

Media Scan works with parity RAID group members, Hot Spare
drives and unallocated drives. Media Scan reads the selected
drives and, if a Media Error is found, Media Scan re-writes
the disk with the media error. The drive will relocate the bad
sector to an alternate part of the drive. Media Scan rewrites the
correct data for a disk that is a member of an on-line parity
RAID group. Media Scan writes random data to Hot Spare drives
and unallocated drives. The Media Scan feature records the
number of media errors detected and corrected for each drive.
These counts are stored persistently if the drive is a RAID group
member or a Hot Spare drive. The counts are not persistently
stored for any other drives.
Media Scan with Parity Verify is a variation of Media Scan that
is available for on-line parity RAID groups only. Parity Verification is
performed on each RAID group stripe that has no detected media
errors. The parity of the stripe is recalculated and compared to
the original parity for the stripe. If there is a mismatch, an error is
generated and recorded in the Event Log and System Log files.
Note: Your computer must be on in order to perform manual or
scheduled Media Scan operations.
Modes of operation for:
• On-line RAID Group – Media Scan performs SCSI Read
commands to each stripe group. Parity verification is performed
on a stripe that has no media errors. Media Scan activity
is scheduled in accordance with the Rebuild Priority Level.
Media Scan is restarted after reboot if the Media Scan did not
complete.
• Degraded or Offline RAID Group – Media Scan performs SCSI
Read commands for each stripe group of the on-line drives. No
parity verification occurs. The Media Scan is restarted after a re-
boot if the Media Scan did not complete.
• Hot Spares & Unallocated Drives – Media Scan performs SCSI
Read commands for each selected drive. Media Scan is not
restarted after a re-boot if the Media Scan did not complete.
Support Note:
impact your Fusion storage system's performance, and
may take several hours to complete. We suggest that you schedule
Media Scan operations for times when the system in not in use.

Start a Manual Media Scan

1. If your computer is running Mac OS X, drag the RAID Group
you want to scan to the trash (changes to an eject icon) to
eject it. Otherwise, skip to step 2.
2. Select the RAID group you want to scan in the Groups pane.
3. Control-click (or right-click) the RAID group and select Media
Scan or Parity Verify (Media Scan + Parity Verify) from the
drop menu. See Figure 23 on page 29. You may also select
RAID Management > Scanning > Media Scan (or RAID
Management > Scanning > Parity Verify) from the application
menu.
4. The scan starts immediately; the Attached Drives pane
displays a rotating icon next to each drive being scanned,
and the RAID Group pane displays the type of scan being
performed and a status for percent complete.

Schedule a Media Scan

1. Select a RAID group in the Groups pane.
2. Control-click (or right-click) the RAID group and select
Schedule. See Figure 24 on page 29. You may also select RAID
Management > Schedule from the application menu.
3. Select Media Scan or Media Scan with Verify, and then
click Next. See Figure 25 on page 30.
4. Select the time and frequency schedule for the task to be
performed. See Figure 26 on page 30.
5. Click Finish, and then click Yes in the next dialog box to
finish scheduling the task.
Note: You may schedule only one task per RAID group.

Cancel, Pause, or Resume a Media Scan

1. Select the RAID group being scanned in the groups pane.
2. Control-click (or right-click) the RAID group and select
Pause Media (or Parity) Scan to pause the Media Scan, or
Cancel to stop the Media Scan. You may also select RAID
Management > Pause Media (or Parity) Scan, or RAID
Management > Cancel from the application menu.
Note: You may resume a paused Media Scan operation by control-
clicking (or right-clicking the RAID group that was being
scanned and selecting Resume Media Scan, or by selecting RAID
Management > Resume from the application menu.
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Media Scan operations significantly