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CONSTELLATION ES.1 SAS PRODUCT MANUAL, REV. G 13
5.2 RELIABILITY AND SERVICE
You can enhance the reliability of Constellation ES.1 disk drives by ensuring that the drive receives adequate cooling. Section 6.0 provides
temperature measurements and other information that may be used to enhance the service life of the drive. Section 10.2 provides
recommended air-flow information.
5.2.1 Annualized Failure Rate (AFR) and Mean Time Between Failure (MTBF)
The production disk drive shall achieve an AFR of 0.73% (MTBF of 1,200,000 hours) when operated in an environment that ensures the
HDA case temperatures do not exceed the values specified in Section 6.5. Operation at case temperatures outside the specifications in
Section 6.5 may increase the product AFR (decrease the MTBF). The AFR (MTBF) is a population statistic not relevant to individual units.
The AFR (MTBF) specification is based on the following assumptions for Enterprise Storage System environments:
• 8,760 power-on hours per year.
• 250 average on/off cycles per year.
• Operations at nominal voltages.
• Systems will provide adequate cooling to ensure the case temperatures specified in Section 6.5 are not exceeded. Temperatures outside
the specifications in Section 6.5 will increase the product AFR and decrease the MTBF.
5.2.2 Preventive maintenance
No routine scheduled preventive maintenance is required.
5.2.3 Hot plugging the drive
When a disk is powered on by switching the power or hot plugged, the drive runs a self test before attempting to communicate on its’
interfaces. When the self test completes successfully, the drive initiates a Link Reset starting with OOB. An attached device should
respond to the link reset. If the link reset attempt fails, or any time the drive looses sync, the drive initiated link reset. The drive will initiate
link reset once per second but alternates between port A and B. Therefore each port will attempt a link reset once per 2 seconds assuming
both ports are out of sync.
If the self-test fails, the drive does not respond to link reset on the failing port.
Note. It is the responsibility of the systems integrator to assure that no temperature, energy, voltage hazard, or ESD potential hazard
is presented during the hot connect/disconnect operation. Discharge the static electricity from the drive carrier prior to insert
-
ing it into the system.
Caution. The drive motor must come to a complete stop prior to changing the plane of operation. This time is required to insure data
integrity.