HP Array Controller HSG V8.7 Software - Manual (Page 86)

3–8 HSG80 User’s Guide
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 3–2 compares different kinds of storagesets to help you
determine which ones satisfy your requirements.
For a comprehensive discussion of RAID, refer to The RAIDBOOK—A
Source Book for Disk Array Technology.
Using Stripesets to Increase I/O Performance
Stripesets enhance I/O performance by spreading the data across
multiple disk drives. Each I/O request is broken into small segments
Table 3–2 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