Avago Technologies 3ware 9650SE-12ML (Channel) - Manual (Page 29)

Monitoring, Maintenance, and Troubleshooting Features
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• Verification and Media Scans. The verify task verifies all redundant
units, and checks for media errors on single disks, spares and RAID 0 unit
members. If the disk drive is part of a redundant unit, error locations that
are found and are deemed repairable are rewritten with the redundant
data. This forces the drive firmware to reallocate the error sectors
accordingly. (For more information, see “About Verification” on
page 162.)
• Error Correction . Bad sectors can be dynamically repaired through error
correction (Dynamic Sector Repair). Reallocation of blocks is based
intelligently on the location of the block in relation to the stripe.
• Scheduled Background Tasks. Initialize, rebuild, verify, and self-test
tasks can all be run in the background, at scheduled times. This lets you
choose a time for these tasks to be run when it will be least disruptive to
your system. You can also define the rate at which background tasks are
performed, specifying whether I/O tasks should be given more processing
time, or background rebuild and verify tasks should be given more
processing time. (For more information, see “Scheduling Background
Tasks” on page 173.)
• Write Cache . Write cache can be enabled or disabled using 3BM,
3DM 2 and CLI. When write cache is enabled, data will be stored in
3ware controller cache and drive cache before the data is committed to
disk. This allows the system to process multiple write commands at the
same time, thus improving performance. However when data is stored in
cache, it could be lost if a power failure occurs. With a Battery Backup
Unit (BBU) installed, the data stored on the 3ware controller can be
restored. (For more information, see “Enabling and Disabling the Unit
Write Cache” on page 118.)
• StorSave ™ Profiles allow you to set the level of protection versus
performance that is desired for a unit when write cache is enabled. (For
more information, see “Setting the StorSave Profile for a Unit” on
page 123.)
• Enclosure Services. Drives, fans, temperature sensors, and power
supplies in supported enclosures can be identified by flashing LEDs so
that you can quickly identify which component needs to be checked or
replaced. For more information, see “Managing an Enclosure” on
page 206.
• Auto Rebuild. For times when you do not have a spare available, setting
the Auto Rebuild policy allows rebuilds to occur with an available drive
or with a failed drive. (For more information, see “Setting the Auto
Rebuild Policy” on page 91.)