Promise Technology SMARTSTOR NS4300N - Manual (Page 167)

Chapter 7: Technology Background
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RAID 10 – Mirror / Stripe
Mirror/Stripe combines both of the RAID 0 and RAID 1 types. RAID 10 can
increase performance by reading and writing data in parallel while protecting data
with duplication. At least four disk drives are needed for RAID 10 to be installed.
With a four-disk-drive RAID Volume, one drive pair is mirrored together then
striped over a second drive pair.
Figure 4. RAID 10 takes a data mirror on one drive pair and stripes it over
two drive pairs
The data capacity RAID 10 Volume equals the capacity of the smallest disk drive
times the number of disk drives, divided by two.
In some cases, RAID 10 offers double fault tolerance, depending on which disk
drives fail.
RAID 10 Volumes on SmartStor consist of four disk drives.
Because all of the available disk drives are used for the RAID Volume, you
cannot set up a spare drive with RAID 10.
Data Stripe
Data
Mirror
disk drives