Specifications

4–8 Planning Storagesets
Choosing a Storageset Type
Different applications may have different storage requirements, so you will probably
want to configure more than one kind of storageset in your subsystem.
All of the storagesets described in this book implement RAID (Redundant Array of
Independent Disks) technology. Consequently, they all share one important feature:
each storageset, whether it contains two disk drives or ten, looks like one large, virtual
disk drive to the host.
Table 4–2 compares different kinds of storagesets to help you determine which ones
satisfy your requirements.
Table 4–2. A Comparison of Different Kinds of Storagesets
Storageset Relative
Availability
Request Rate (Read/
Write)
I/O per second
Transfer Rate (Read/
Write) MB per
second
Applications
Array of disk drives
(JBOD)
Equivalent to a single
disk drive
Identical to single
disk drive
Identical to single
disk drive
Stripeset
(RAID 0)
Proportionate to
number of disk
drives; worse than
single disk drive
Excellent if used with
large chunk size
Excellent if used with
small chunk size
High performance
for non-critical
data
Mirrorset
(RAID1)
Excellent Good/Fair Good/Fair System drives;
critical files
RAIDset
(RAID 3/5)
Excellent Excellent/Fair Good/Poor High request
rates, read-
intensive, data
lookup
Striped Mirrorset
(RAID 0+1)
Excellent Excellent if used with
large chunk size
Excellent if used with
small chunk size
Any critical
response-time
application