TeraStation User Manual
18
Chapter 3
Changing RAID Modes
TS-XL, TS-XEL and TS-RXL series TeraStations default to RAID 5 mode (4 hard drives), TS-WXL/R1 series default to RAID
1 mode, and TS-WXL/1D series default to Normal mode. The characteristics of each type of RAID are described below.
If you change the RAID mode, all of the data on the hard drive is deleted. Always back up any important data before
changing the RAID mode.
Note:
In this document, the term “Recovery” means reverting the TeraStation back to the state prior to the drive error or RAID
mode change. It does not refer to reading data from failed hard drives.
• RAID 5 mode (4 hard drives) (Default for TS-XL, TS-XEL and TS-RXL)
Note:
TS-WXL/R1 and TS-WXL/1D TeraStations don’t support this mode, as they don’t have 4 hard drives.
Arranges 4 hard drives in one array. Parity is generated during writes, so access speeds will be slower than other RAID
modes. Total usable space is the sum of the 3 drives. If one of the drives fails, you can recover data on the array by
replacing the damaged drive. However, data cannot be recovered if 2 or more drives become damaged.
• RAID 5 mode (3 hard drives)
Note:
TS-WXL/R1 and TS-WXL/1D TeraStations don’t support this mode, as they don’t have 3 hard drives.
Arranges 3 hard drives in one array. Parity is generated during writes, so access speeds will be slower than other RAID
modes. Total usable space is the sum of 2 drives. A fourth drive may be configured as a hot spare that will automatically
replace a drive if it fails. If one of the drives fails, you can recover data on the array by replacing the damaged drive.
However, data cannot be recovered if 2 or more drives become damaged.
• RAID 10 mode
Note:
TS-WXL/R1 and TS-WXL/1D TeraStations don’t support this mode, as they don’t have 4 hard drives
Arranges 4 hard drives in one array, with 2 stripes of mirrored drives. Total usable space is the sum of 2 hard drives. Data
is written quickly and access speed is faster than other RAID modes (except for RAID 0). Since data is written into 2 hard
drives at the same time, even if one of the drives fails, data can still be recovered by replacing the damaged drive (data
cannot be recovered if both drives become damaged).
RAID Arrays