6.1.3Seek 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 positioning 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 108 seeks. Unrecoverable seek errors (Sense Key = 04h) are classified as drive failures.
6.1.4Interface 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.
6.2Reliability and service
You can enhance the reliability of Constellation.2 disk drives by ensuring that the drive receives adequate cool- ing. Section 7.0 provides temperature measurements and other information that may be used to enhance the service life of the drive. Section 11.2 provides recommended
6.2.1Annualized 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 7.5. Oper- ation at case temperatures outside the specifications in Section 7.5 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 environ- ments:
•8760
•250 average on/off cycles per year.
•Operations at nominal voltages.
•Systems will provide adequate cooling to ensure the case temperatures specified in Section 7.5 are not exceeded. Temperatures outside the specifications in Section 7.5 will increase the product AFR and decrease the MTBF.
6.2.2Preventive maintenance
No routine scheduled preventive maintenance is required.
6.2.3Hot 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
Note. It is the responsibility of the systems integrator to assure that no temperature, energy, voltage haz- ard, 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.
16 | Constellation.2 SAS Product Manual, Rev. H |
