User Manual

Constellation ES.3 SAS Product Manual, Rev. F 20
Predictive failures
S.M.A.R.T. signals predictive failures when the drive is performing unacceptably for a period of time. The firmware keeps a running
count of the number of times the error rate for each attribute is unacceptable. To accomplish this, a counter is incremented each time
the error rate is unacceptable and decremented (not to exceed zero) whenever the error rate is acceptable. If the counter continually
increments such that it reaches the predictive threshold, a predictive failure is signaled. This counter is referred to as the Failure
History Counter. There is a separate Failure History Counter for each attribute.
5.2.4 Thermal monitor
Constellation ES.3 drives implement a temperature warning system which:
1. Signals the host if the temperature exceeds a value which would threaten the drive.
2. Signals the host if the temperature exceeds a user-specified value.
3. Saves a S.M.A.R.T. data frame on the drive which exceeds the threatening temperature value.
A temperature sensor monitors the drive temperature and issues a warning over the interface when the temperature exceeds a set
threshold. The temperature is measured at power-up and then at ten-minute intervals after power-up.
The thermal monitor system generates a warning code of 01-0B01 when the temperature exceeds the specified limit in compliance
with the SCSI standard. The drive temperature is reported in the FRU code field of mode sense data. Users can use this information to
determine if the warning is due to the temperature exceeding the drive threatening temperature or the user-specified temperature.
This feature is controlled by the Enable Warning (EWasc) bit, and the reporting mechanism is controlled by the Method of Reporting
Informational Exceptions field (MRIE) on the Informational Exceptions Control (IEC) mode page (1Ch).
The current algorithm implements two temperature trip points. The first trip point is set at 65°C which is the maximum temperature
limit according to the drive specification. The second trip point is user-selectable using the Log Select command. The reference
temperature parameter in the temperature log page (see Table 1) can be used to set this trip point. The default value for this drive is
65°C, however, users can set it to any value in the range of 0 to 65°C. If users specify a temperature greater than 65°C in this field, the
temperature is rounded down to 65°C. A sense code is sent to the host to indicate the rounding of the parameter field.
5.2.5 Drive Self Test (DST)
Drive Self Test (DST) is a technology designed to recognize drive fault conditions that qualify the drive as a failed unit. DST validates
the functionality of the drive at a system level.
There are two test coverage options implemented in DST:
1. Extended test
2. Short test
The most thorough option is the extended test that performs various tests on the drive and scans every logical block address (LBA) of
the drive. The short test is time-restricted and limited in length—it does not scan the entire media surface, but does some
fundamental tests and scans portions of the media.
If DST encounters an error during either of these tests, it reports a fault condition. If the drive fails the test, remove it from service and
return it to Seagate for service.
Table 1: Temperature Log Page (0Dh)
Parameter Code Description
0000h
Primary Temperature
0001h
Reference Temperature