Seagate ST336754SS Cheetah 15K.4 SAS Product Manual - Page 50

40

Cheetah 15K.4 SAS Product Manual, Rev. B

When the RC bit is one, reallocations are disabled even if the ARRE or AWRE bits are one. The drive will still

perform data recovery actions within the limits defined by the Read Retry Count, Write Retry Count, and

Recovery Time Limit parameters. However, the drive does not report any unrecovered errors.

[1]

Setting these retry counts to a value below the default setting could result in degradation of the unrecov-

ered error rate which may exceed the value given in this product manual. A setting of zero (0) will result in

the drive not performing error recovery.

For example, suppose the read/write recovery page has the RC bit set to 0, read retry count set to 4, and

the recovery time limit field (Mode Sense page 01, bytes 10 and 11) set to FF FF hex (maximum). A four

LBA Read command is allowed to take up to 271.32 msec recovery time for each of the four LBAs in the

command. If the recovery time limit is set to 00 C8 hex (200 msec decimal) a four LBA read command is

allowed to take up to 200 msec for all error recovery within that command. The use of the Recovery Time

Limit field allows finer granularity on control of the time spent in error recovery. The recovery time limit

only starts counting when the drive is executing error recovery and it restarts on each command. There-

fore, each command’s total recovery time is subject to the recovery time limit. Note: A recovery time limit

of 0 will use the drive’s default value of FF FF. Minimum recovery time limit is achieved by setting the

Recovery Time Limit field to 00 01.

7.3

SAS system errors

Information on the reporting of operational errors or faults across the interface is given in the

SAS Interface

Manual

. The SSP Response returns information to the host about numerous kinds of errors or faults. The

Receive Diagnostic Results reports the results of diagnostic operations performed by the drive.

Status returned by the drive to the initiator is described in the

SAS Interface Manual.

Status reporting plays a

role in systems error management and its use in that respect is described in sections where the various com-

mands are discussed.

Table 5:

Read and write retry count maximum recovery times

Read retry count

1

Maximum recovery time per

LBA (cumulative, msec)

Write retry count

1

Maximum recovery time per

LBA (cumulative, msec)

0

51.87

0

23.94

1

59.85

1

35.91

2

203.49

2

55.86

3

235.41

3

67.83

4

271.32

4

119.7

5

283.29

5 (default)

147.63

6

315.21

7

395.01

8

454.86

9

486.78

10

522.69

11 (default)

1,264.83

Section	Page
1.0 Scope	11
2.0 Standards, compliance and reference documents	13
2.1 Standards	13
2.1.1 Electromagnetic compatibility	13
2.1.1.1 Electromagnetic susceptibility	13
2.2 Compliance	14
2.2.1 Electromagnetic compliance	14
2.3 Reference documents	15
3.0 General description	17
3.1 Standard features	18
3.2 Media description	18
3.3 Performance	18
3.4 Reliability	19
3.5 Formatted capacities	19
3.6 Programmable drive capacity	19
3.7 Factory-installed accessories	19
3.8 Factory-installed options	20
3.9 User-installed accessories	20
4.0 Performance characteristics	21
4.1 Internal drive characteristics	21
4.2 Seek performance characteristics	21
4.2.1 Access time	21
4.2.2 Format command execution time (minutes)	22
4.2.3 General performance characteristics	22
4.3 Start/stop time	22
4.4 Prefetch/multi-segmented cache control	23
4.5 Cache operation	23
4.5.1 Caching write data	24
4.5.2 Prefetch operation	24
4.5.3 Optimizing cache performance for desktop and server applications	25
5.0 Reliability specifications	27
5.1 Error rates	27
5.1.1 Recoverable Errors	27
5.1.2 Unrecoverable Errors	27
5.1.3 Seek errors	28
5.1.4 Interface errors	28
5.2 Reliability and service	28
5.2.1 Annualized Failure Rate (AFR)	28
5.2.2 Preventive maintenance	28
5.2.3 Hot plugging the drive	28
5.2.4 S.M.A.R.T.	29
5.2.5 Thermal monitor	30
5.2.6 Drive Self Test (DST)	31
5.2.6.1 DST failure definition	31
5.2.6.2 Implementation	31
5.2.6.2.1 State of the drive prior to testing	32
5.2.6.2.2 Invoking DST	32
5.2.6.2.3 Short and extended tests	32
5.2.6.2.4 Log page entries	32
5.2.6.2.5 Abort	33
5.2.7 Product warranty	33
6.0 Physical/electrical specifications	35
6.1 AC power requirements	35
6.2 DC power requirements	35
6.2.1 Conducted noise immunity	37
6.2.2 Power sequencing	37
6.2.3 Current profiles	37
6.3 Power dissipation	41
6.4 Environmental limits	44
6.4.1 Temperature	44
6.4.2 Relative humidity	45
6.4.3 Effective altitude (sea level)	45
6.4.4 Shock and vibration	45
6.4.4.1 Shock	45
6.4.4.2 Vibration	47
6.4.5 Air cleanliness	47
6.4.6 Corrosive environment	47
6.4.7 Acoustics	48
6.4.8 Electromagnetic susceptibility	48
6.5 Mechanical specifications	48
7.0 Defect and error management	49
7.1 Drive internal defects/errors	49
7.2 Drive error recovery procedures	49
7.3 SAS system errors	50
8.0 Installation	51
8.1 Drive orientation	51
8.2 Cooling	52
8.3 Drive mounting	53
8.4 Grounding	53
9.0 Interface requirements	55
9.1 SAS features	55
9.1.1 task management functions	55
9.1.2 task management responses	55
9.2 Dual port support	56
9.3 SCSI commands supported	57
9.3.1 Inquiry data	61
9.3.2 Mode Sense data	61
9.3.2.1 ST3146854SS Mode Sense data	63
9.3.2.2 ST373454SS Mode Sense data	64
9.3.2.3 ST336754SS Mode Sense data	65
9.4 Miscellaneous operating features and conditions	66
9.4.1 SAS physical interface	67
9.4.2 Physical characteristics	69
9.4.3 Connector requirements	69
9.4.4 Electrical description	70
9.4.5 Pin descriptions	70
9.4.6 SAS transmitters and receivers	71
9.4.7 Power	71
9.5 Signal characteristics	71
9.5.1 Ready LED Out	71
9.5.2 Differential signals	72
9.5.2.1 Eye masks	72
9.5.2.1.1 Eye masks overview	72
9.5.2.1.2 Receive eye mask	73
9.5.2.1.3 Jitter tolerance masks	73
9.5.2.2 Transmitter signal characteristics	75
9.5.2.3 Receiver signal characteristics	76
9.5.2.3.1 Jitter	76
9.5.2.3.2 Receiver jitter tolerance	77
9.5.2.3.3 Compliant jitter test pattern (CJTPAT)	77
9.5.2.3.4 Impedance specifications	77
9.5.2.4 Electrical TxRx connections	78
9.5.2.4.1 Transmitter characteristics	78
9.5.2.5 Receiver characteristics	81
10.0 Seagate Technology support services	83
Numerics	89
A	89
B	89
C	89
D	89
E	89
F	90
G	90
H	90
I	90
J	90
L	90
M	90
N	91
O	91
P	91
Q	91
R	91
S	91
T	92
U	92
V	92
W	92

Seagate ST336754SS Cheetah 15K.4 SAS Product Manual - Page 50

SAS system errors

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