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3ware® User Guide > Configuring Units > Setting Unit Policies > Rapid RAID Recovery

Rapid RAID Recovery
The Rapid Raid Recovery feature increases the speed with which a redundant unit can be made redundant again when a rebuild is required. It can also increase the speed of verification or initialization that may occur in the event of an unclean shutdown.
Rapid RAID Recovery is possible because the firmware maps the unit, and tracks the areas of the unit where write activity occurs. Then, if a rebuild, initialization, or verify is required, the controller only has to address the active areas. The fewer active areas, the faster the rebuild, initialize or verify.
Since the units are mapped out and tracked from the creation of the unit, this feature can only be enabled during unit creation. Also, once disabled, it cannot be re-enabled.
If all of a unit’s capacity is being used, there is no real advantage to Rapid RAID Recovery, but the more your unit’s capacity is under-utilized, the less time a rebuild, initialization or verify will take if you enable Rapid RAID Recovery.
Possible settings are All (labeled Fast Rebuild/Shutdown in 3BM), Rebuild or Disable. All will apply the policy to both rebuilds and unclean shutdowns. Rebuild will apply only to rebuilds. Disable means that rebuilds, initializations and verifies will take place on the entire unit, not just the active sections. The default setting is All.
There is some system overhead from setting rapid recovery to All. If you have a BBU, you can set rapid recovery to Rebuild, as a BBU provides protection against data loss in the event of an unclean shutdown.
Some limitations of Rapid RAID Recovery:
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Currently Rapid RAID Recovery only works with FAT, FAT32 and NTFS file systems. Linux or FreeBSD file systems such as Ext3 are not yet supported.
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Units with Rapid RAID Recovery enabled will not be readable if moved to controllers using pre-9.5.1 firmware. If you wish to move the unit to a controller with pre-9.5.1 firmware, you must first disable Rapid RAID Recovery.
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Units created on controllers with pre-9.5.1 firmware will not be able to take advantage of Rapid RAID Recovery when the controller is updated to 9.5.1 or later. These units will show Rapid RAID Recovery as disabled.
Changing or disabling Rapid RAID Recovery
Rapid RAID Recovery can only be enabled (that is - set to All or Rebuild) when the unit is created. You can change between All and Rebuild at any time. However, if you disable Rapid RAID Recovery, you cannot then enable it.
To change or disable Rapid RAID Recovery for an existing unit through 3DM
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Choose Management > Controller Settings from the menu bar in 3DM.
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In the Unit Policies section of the Controller Settings page, select All, Rebuild, or Disable from the Rapid RAID Recovery dropdown menu.
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The page refreshes, and a message at the top confirms the change that you have made.
To change or disable Rapid RAID Recovery for an existing unit through 3BM
1
An asterisk appears in the left-most column to indicate that it is selected.
2
Tab to the Maintain Unit button and press Enter.
3
On the pop-up menu, select Configure and press Enter.
4
In the Configure Disk Array screen, Tab to the field Rapid RAID Recovery and select Fast Rebuild/Shutdown, Rebuild, or Disable.
A warning message appears, asking you to confirm your selection.
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