Seagate ST3300457FC Cheetah 15K.7 SAS Product Manual - Page 20

Seek errors, Interface errors, Annualized Failrue Rate AFR and Mean time between failure MTBF,

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6.1.3 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 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. 6.1.4 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. 6.2 Reliability and service You can enhance the reliability of Cheetah disk drives by ensuring that the drive receives adequate cooling. 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 air-flow information. 6.2.1 Annualized Failrue Rate (AFR) and Mean time between failure (MTBF) These drives shall achieve an AFR of 0.55% (MTBF of 1,600,000 hours) when operated in an environment that ensures the HDA case temperatures do not exceed the values specified in Section 7.4. Operation at case temperatures outside the specifications in Section 7.4 may increase the AFR (decrease the MTBF). AFR and MTBF statistics are population statistics that are not relevant to individual units. AFR and MTBF specifications are 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 7.4.1 are not exceeded. 6.2.2 Preventive maintenance No routine scheduled preventive maintenance is required. 6.2.3 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 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. 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. 14 Cheetah 15K.7 SAS Product Manual, Rev. C

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14
Cheetah 15K.7 SAS Product Manual, Rev. C
6.1.3
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 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 10
8
seeks.
Unrecoverable seek errors
(Sense Key = 04h) are classified as drive failures.
6.1.4
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.
6.2
Reliability and service
You can enhance the reliability of Cheetah disk drives by ensuring that the drive receives adequate cooling.
Section 7.0 provides temperature measurements and other information that may be used to enhance the ser-
vice life of the drive. Section 11.2 provides recommended air-flow information.
6.2.1
Annualized Failrue Rate (AFR) and Mean time between failure (MTBF)
These drives shall achieve an AFR of 0.55% (MTBF of 1,600,000 hours) when operated in an environment that
ensures the HDA case temperatures do not exceed the values specified in Section 7.4.
Operation at case temperatures outside the specifications in Section 7.4 may increase the AFR (decrease the
MTBF). AFR and MTBF statistics are population statistics that are not relevant to individual units.
AFR and MTBF specifications are based on the following assumptions for Enterprise Storage System environ-
ments:
•
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 7.4.1 are not
exceeded.
6.2.2
Preventive maintenance
No routine scheduled preventive maintenance is required.
6.2.3
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 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 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.
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.