User guide

1-10 Compaq StorageWorks RAID Array 4100 User Guide
Performance Monitoring
Compaq Insight Manager can be used to monitor the performance of several
RA4000 Controller parameters. The displayed parameters include CPU usage,
total number of read and write commands processed, and average time to
process a read or write command. Also displayed for each logical drive are
total I/O count, number of read and write requests, and number of sectors read
or written. Use Insight Manager to monitor the performance of your drive
arrays.
Automatic Performance Tuning
The RA4000 Controller has the ability to adjust or tune its performance
without manual intervention. For example, if caching is enabled but the
RA4000 Controller determines that it is no longer beneficial, caching is
automatically disabled. If write or read-ahead caching would improve
performance, but it has been automatically disabled, the RA4000 Controller
enables it again.
Tagged-Command Queuing
The RA4000 Controller also supports tagged-command queuing. This allows
SCSI hard drives to queue and sort multiple commands, then execute the
commands in the optimal order for highest drive performance.
System Power
System power in the Compaq RA4100 does not shut off completely with the
power switch. The two positions of the front panel power switch should be
considered as ON and STANDBY, rather than ON and OFF. The STANDBY
position removes power from most of the electronics and the drives, but
portions of the power supply and some internal circuitry remain active.
Consequently, to remove all power from the system, you must disconnect the
power cord from the storage system. In systems with multiple power supplies,
you must disconnect all the power cords to remove power completely from the
system.
WARNING: To reduce the risk of electric shock or damage to the equipment,
disconnect power from the storage system by unplugging all power cords from
either the electrical outlet or the storage system.