Buffalo HD-QLU3R5, User Manual

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12 HD-QLU3 User Manual
Building RAID Arrays
The four internal hard drives of the DriveStation can be configured into a RAID array for use as a single
hard drive. The RAID array can also be reset and rebuilt using the procedures below.
Notes on Building a RAID Array
•
When building a RAID array, connect the DriveStation with a USB cable and disconnect all other USB
devices. The RAID array may not be built correctly if other USB devices are connected.
• When building a RAID array, all data stored on the DriveStation is lost. Be sure to back up your data
before building the RAID array.
What is RAID?
RAID is a system of combining multiple hard drives for use as a single hard drive, increasing hard drive
speed, and enabling easy recovery in the event of hard drive failure. The DriveStation uses four hard
drives to build the RAID. The RAID level is determined based on how the hard drives are combined. The
RAID levels supported by the DriveStation are shown below.
■
RAID 5 Mode (Default setting: Enables high-speed access and
secure storage of data)
Parity (error-correcting code) is generated from the data, and this code is saved and distributed to
multiple hard drives together with the data. If any one of the hard drives fails, the data can be recovered
by replacing the hard drive and comparing with the parity of the surrounding data. The OS only
recognizes the capacities of three hard drives. Because the data is distributed when it is saved, this
enables faster hard drive access than using a single hard drive.
• Example of Hard Drive Configuration
Configuration using HD-QL4TU3R5: Recognized as a 3 TB (1 TB×3) hard drive
Data
①②③④
⑤⑥⑦⑧
Parity (P) is
generated and saved.
Even if one hard
drive fails, data can
be recovered by
comparing the parity.
Data
③Ｐ⑧
Data
Ｐ⑥
Total usable capacity is
the sum of the capacity
of three drives and data
protection is provided
Data
①④⑦
Data
②⑤Ｐ