NEC Storage Performance Monitor/Optimizer User Manual page 181

Appendix F Example of Performance Improvement
Client's log-in
Mail message sending/receiving by clients
Write I/O counts
Read I/O counts
Total I/O counts
Number of writing
accesses is greater
than that of reading
accesses.
On the basis of study of the graph, the system is analyzed and possible actions are suggested as
follows:
Analysis
Number of writing access is greater than
reading accesses.
Accesses exceeding disk performance limit
are occurring.
Client's log-off
Time
RAID5 has a risk of excessive loads on disk
by write penalty. RAID10 is more suitable
for a system expecting massive write accesses.
Change RAID configuration into RAID10.
Add extra disk devices to distribute the loads.
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Limit of disk capability
is 30000 to 40000
messages/5 minutes
Number of disk I/O
accesses increases
when clients'
sending/receiving
messages and logging
off occurs
concurrently, and it
exceeds disk
capabilities.
Stable operations are
expected under
operation of using
60% to 70% of total
disk capability.
Addition of extra disk
devices is desired.
Action