Buffalo terastation 3000, User Manual

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Chapter 4 Storage Management
RAID Modes
TeraStations support many types of RAID. The type of RAID arrays available for use depends on how many drives are
installed in your TeraStation.
Notes:
• If you change the RAID mode, all data on the array is deleted. This is true for every procedure in this chapter.
Always back up any important data before performing actions that affect your RAID array.
• Drive capacity is displayed in Settings in actual gigabytes. The Properties window in Windows may show GiB
instead, which will be a smaller number.
• After the RAID mode is changed (except when creating a RAID 0 array or JBOD), the TeraStation performs a RAID
check that will take about 10 hours per TB. File transfers are slower during this period. While the I17 message
appears on the LCD panel, do not turn off the TeraStation. If you do, the RAID check starts over.
• If the TeraStation is restarted or shut down while changing the RAID mode, the message that appears on the LCD
panel will change from I46 or I47 to I18.
• RAID 5, 6, and 10 are only available for models with 4 drives.
RAID 6
RAID 6 arrays are available for TeraStations with 4 or more drives. RAID 6 combines 4 or more drives into a single
array. The usable space is equal to the sum of the capacity of all drives minus the capacity of two drives. For example,
if 4 drives are combined into a RAID 6 array, the usable space is the sum of the capacity of 2 drives. If 2 drives in the
array are damaged, you can recover data by replacing them. If 3 or more drives are damaged, your data is lost.
RAID 5
RAID 5 arrays are available for TeraStations with 3 or more drives. RAID 5 combines 3 or more drives into a single
array. The usable space is equal to the sum of the capacity of the drives minus the capacity of one drive. For
example, if 4 drives are combined into a RAID 5 array, the usable space is the sum of 3 drives. If one drive in the array
is damaged, you can recover data by replacing the damaged drive. If two or more drives are damaged at the same
time, your data is lost.
RAID 10
RAID 10 arrays are available for TeraStations with 4 or more drives. In this mode, mirrored pairs of drives in RAID 1
arrays are combined into a RAID 0 array. The usable space is equal to the capacity of the smallest drive multiplied by
the number of drives divided by 2.
RAID 1
Combines 2 or more drives into a mirrored array. The available space in the array is the capacity of a single drive.
Identical data is written to each drive. If a drive is damaged, data can be recovered by replacing the damaged drive.
As long as one drive in the array remains undamaged, all data in the array can be recovered.
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