User Manual

Constellation.2 SAS Product Manual, Rev. K 21
5.1.3 Seek errors
A seek error is defined as a failure of the drive to position the heads to the addressed track. After detecting an initial
seek error, the drive automatically performs an error recovery process. If the error recovery process fails, a seek posi-
tioning error (Error code = 15h or 02h) will be reported with a Hardware error (04h) in the Sense Key. Recoverable
seek errors are specified at Less than 10 errors in 10
8
seeks. Unrecoverable seek errors (Sense Key = 04h) are classified
as drive failures.
5.1.4 Interface errors
An interface error is defined as a failure of the receiver on a port to recover the data as transmitted by the device port
connected to the receiver. The error may be detected as a running disparity error, illegal code, loss of word sync, or
CRC error.
5.2 Reliability and service
You can enhance the reliability of Constellation®.2 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 0.62% (MTBF of 1,400,000 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 tempera-
tures 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:
• 8760 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 inserting it into the system.