Seagate (ST16000NM002G) - Инструкция по эксплуатации - Страница 17

Seagate Exos X16 SAS Product Manual, Rev. K

16 

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Reliability specifications

5.0

Reliability specifications

The following reliability specifications assume correct host and drive operational interface, including all interface timings, power supply voltages, 
environmental requirements and drive mounting constraints. 

5.1

Error rates 

The error rates stated in this manual assume the following: 

• The drive is operated in accordance with this manual using DC power as defined in 

Section 6.4, 

DC power requirements

• Errors caused by host system failures are excluded from error rate computations.
• Assume random data.
• Default OEM error recovery settings are applied. This includes AWRE, ARRE, full read retries, full write retries and full retry time.

5.1.1

Recoverable Errors

Recoverable errors are those detected and corrected by the drive, and do not require user intervention.

Recoverable Data errors will use correction, although ECC on-the-fly is not considered for purposes of recovered error specifications.

Recovered Data error rate is determined using read bits transferred for recoverable errors occurring during a read, and using write bits transferred

for recoverable errors occurring during a write.

5.1.2

Unrecoverable Errors

An unrecoverable data error is defined as a failure of the drive to recover data from the media. These errors occur due to head/media or write

problems. Unrecoverable data errors are only detected during read operations, but not caused by the read. If an unrecoverable data error is 
detected, a MEDIUM ERROR (03h) in the Sense Key will be reported. Multiple unrecoverable data errors resulting from the same cause are treated

as 1 error.

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 per forms 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.

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. 

Seek error rate:

Less than 10 errors in 10

8

seeks

Read Error Rates

1

1.

Error rate specified with automatic retries and data correction with ECC enabled and all flaws reallocated.

2.

See 

Section 5.2, "Reliability and service"

 for rated MTBF device operating condition requirements.

Recovered Data

Less than 10 errors in 10

12

 bits transferred (OEM default settings)

Unrecovered Data

Less than 1 sector in 10

15

 bits transferred

Miscorrected Data

Less than 1 sector in 10

21

 bits transferred

Interface error rate:

Less than 1 error in 10

12

 bits transferred 

Mean Time Between Failure (MTBF):

2,500,000 hours

Annualized Failure Rate (AFR):

2

0.35%

Preventive maintenance:

None required