Seagate ST3300457FC Cheetah 15K.7 SAS Product Manual - Page 47

Cheetah 15K.7 SAS Product Manual, Rev. C

41

[1]

These values are subject to change.

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 253.11 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.

10.3

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.

10.4

Background Media Scan

Background Media Scan (BMS) is a self-initiated media scan. BMS is defined in the T10 document SPC-4

available from the T10 committee. BMS performs sequential reads across the entire pack of the media while

the drive is idle. In RAID arrays, BMS allows hot spare drives to be scanned for defects prior to being put into

service by the host system. On regular duty drives, if the host system makes use of the BMS Log Page, it can

avoid placing data in suspect locations on the media. Unreadable and recovered error sites will be logged or

reallocated per ARRE/AWRE settings.

Table 16:

Read and write retry count maximum recovery times [1]

Read retry

count

Maximum recovery time per LBA

(cumulative, msec)

Write retry

count

Maximum recovery time per LBA

(cumulative, msec)

0

51.87

0

23.94

1

59.85

1

35.91

2

203.49

2

39.9

3

231.42

3

51.87

4

295.26

4

79.8

5

327.18

5 (default)

107.73

6

359.10

7

446.88

8

538.65

9

570.57

10

598.50

11 (default)

1,534.97

Section	Page
1.0 Seagate Technology support services	7
2.0 Scope	8
3.0 Standards, compliance and reference documents	9
3.1 Standards	9
3.1.1 Electromagnetic compatibility	9
3.1.1.1 Electromagnetic susceptibility	9
3.2 Compliance	10
3.2.1 Electromagnetic compliance	10
3.3 European Union Restriction of Hazardous Substances (RoHS)	10
3.4 Reference documents	11
4.0 General description	12
4.1 Standard features	13
4.2 Media description	13
4.3 Performance	13
4.4 Reliability	14
4.5 Formatted capacities	14
4.6 Programmable drive capacity	14
4.7 Factory-installed options	14
5.0 Performance characteristics	15
5.1 Internal drive characteristics	15
5.2 Seek time	15
5.2.1 Access time	15
5.2.2 Format command execution time (minutes)	16
5.2.3 General performance characteristics	16
5.3 Start/stop time	16
5.4 Prefetch/multi-segmented cache control	17
5.5 Cache operation	17
5.5.1 Caching write data	18
5.5.2 Prefetch operation	18
6.0 Reliability specifications	19
6.1 Error rates	19
6.1.1 Recoverable Errors	19
6.1.2 Unrecoverable Errors	19
6.1.3 Seek errors	20
6.1.4 Interface errors	20
6.2 Reliability and service	20
6.2.1 Annualized Failrue Rate (AFR) and Mean time between failure (MTBF)	20
6.2.2 Preventive maintenance	20
6.2.3 Hot plugging the drive	20
6.2.4 S.M.A.R.T.	21
6.2.5 Thermal monitor	22
6.2.6 Drive Self Test (DST)	23
6.2.6.1 DST failure definition	23
6.2.6.2 Implementation	23
6.2.7 Product warranty	25
7.0 Physical/electrical specifications	26
7.1 AC power requirements	26
7.2 DC power requirements	26
7.2.1 Conducted noise immunity	30
7.2.2 Power sequencing	30
7.2.3 Current profiles	30
7.3 Power dissipation	33
7.4 Environmental limits	35
7.4.1 Temperature	35
7.4.2 Relative humidity	36
7.4.3 Effective altitude (sea level)	36
7.4.4 Shock and vibration	36
7.4.4.1 Shock	36
7.4.4.2 Vibration	38
7.4.5 Acoustics	39
7.4.6 Air cleanliness	39
7.4.7 Corrosive environment	39
7.4.8 RoHS compliance statement	39
7.4.9 Electromagnetic susceptibility	40
7.5 Mechanical specifications	40
8.0 About FIPS	41
9.0 About self-encrypting drives	42
9.1 Data encryption	42
9.2 Controlled access	42
9.2.1 Admin SP	42
9.2.2 Locking SP	42
9.2.3 Default password	43
9.3 Random number generator (RNG)	43
9.4 Drive locking	43
9.5 Data bands	43
9.6 Cryptographic erase	43
9.7 Authenticated firmware download	43
9.8 Power requirements	44
9.9 Supported commands	44
10.0 Defect and error management	45
10.1 Drive internal defects/errors	45
10.2 Drive error recovery procedures	45
10.3 SAS system errors	47
10.4 Background Media Scan	47
10.5 Media Pre-Scan	48
10.6 Deferred Auto-Reallocation	48
10.7 Idle Read After Write	48
11.0 Installation	49
11.1 Drive orientation	49
11.2 Cooling	49
11.3 Drive mounting	50
11.4 Grounding	50
12.0 Interface requirements	51
12.1 SAS features	51
12.1.1 task management functions	51
12.1.2 task management responses	51
12.2 Dual port support	52
12.3 SCSI commands supported	52
12.3.1 Inquiry data	56
12.3.2 Mode Sense data	57
12.3.2.1 600GBmodel Mode Sense data	58
12.3.2.2 450GB model Mode Sense data	60
12.3.2.3 300GB model Mode Sense data	62
12.4 Miscellaneous operating features and conditions	63
12.4.1 SAS physical interface	64
12.4.2 Physical characteristics	66
12.4.3 Connector requirements	66
12.4.4 Electrical description	67
12.4.5 Pin descriptions	67
12.4.6 SAS transmitters and receivers	68
12.4.7 Power	68
12.5 Signal characteristics	68
12.5.1 Ready LED Out	68
12.5.2 Differential signals	69
12.6 SAS-2 Specification compliance	69
12.7 Additional information	69
Numerics	71
A	71
B	71
C	71
D	71
E	72
F	72
G	72
H	72
I	72
J	72
L	72
M	72
N	73
O	73
P	73
Q	73
R	73
S	73
T	74
U	74
V	74
W	74

Seagate ST3300457FC Cheetah 15K.7 SAS Product Manual - Page 47

SAS system errors, Background Media Scan

Page 47 highlights