Choosing A Raid Level - Promise Technology SmartStor NAS Product Manual

SmartStor NAS Product Manual
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.

7.2 Choosing a RAID Level

There are several issues to consider when choosing the RAID level for your
Volume. The following discussion summarizes some advantages,
disadvantages and applications for each choice.
RAID 0
Advantages
Implements a striped disk RAID
Volume, the data is broken down into
blocks and each block is written to a
separate disk drive
I/O performance is greatly improved
by spreading the I/O load across
many channels and drives
No parity calculation overhead is
involved
Recommended applications for RAID 0:
Image Editing
․
Data Stripe
Disk drives
Disadvantages
Not a true RAID because it is not fault
tolerant
The failure of just one drive will result
in all data in an RAID Volume being
lost
Should not be used in mission critical
environments
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Data Mirror