Choosing A Storageset Type - Compaq StorageWorks HSZ80 Configuration And Cli Reference Manual

3–8 Creating 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 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.
Table 3–2 A Comparison of Different Kinds of Storagesets
Storageset Type
Availability
Array of disk Equivalent to a
drives (JBOD) single disk drive
Stripeset Proportionate to
(RAID 0) number of disk
drives; worse than
single disk drive
Mirrorset Excellent
(RAID1)
RAIDset Excellent
(RAID 3/5)
Striped Mirrorset Excellent
(RAID 0+1)
For a comprehensive discussion of RAID, refer to The RAIDBOOK—A Source Book
for Disk Array Technology.
Relative Request Rate
(Read/Write) I/O per
second
Identical to single
disk drive
Excellent if used
with large chunk
size
Good/Fair
Excellent/Fair
Excellent if used
with large chunk
size
Transfer Rate (Read/
Write) MB per
second
Identical to single
disk drive
Excellent if used High performance for
with small chunk noncritical data
size
Good/Fair System drives; critical
files
Good/Poor High request rates,
read-intensive, data
lookup
Excellent if used Any critical response-
with small chunk time application
size
Applications