Seagate Nytro 2.5” x 7mm SSD Product Manual, Rev. A
18
Interface requirements
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3.4
SMART Attributes
The following table lists the supported SMART attributes.
Table 20 SMART Attributes (Log Identifier 02h)
Byte
# of Bytes
Attribute
Description
0
1
Critical Warning:
These bits, if set, flag various warning sources.
Bit 0: Available Spare is below Threshold
Bit 1: Temperature has exceeded Threshold
Bit 2: Reliability is degraded due to excessive
media or internal errors
Bit 3: Media is placed in Read- Only Mode
Bit 4: Volatile Memory Backup System has failed
(e.g., enhanced power loss capacitor test failure)
Bits 5-7: Reserved
Any of the critical warning can be tied to
asynchronous event notification. Drive
Health Indicator defined under bytes 3095-
3076 of Identify Controller may still indicate
"healthy" status when the critical warning flag
is set.
1
2
Temperature:
Overall Device current temperature in Kelvin
For AIC, this reports the NAND temperature, for
2.5-inch FF, this reports the case
temperature,
3
1
Available Spare: Contains a normalized percentage
(0 to 100%) of the remaining spare capacity available
Starts from 100 and decrements.
4
1
Available Spare Threshold
Threshold is set to 10%.
5
1
Percentage Used Estimate
(Value allowed to exceed 100%)
A value of 100 indicates that the estimated
endurance of the device has been
consumed, but may not indicate a device fail-
ure. The value is allowed to exceed 100. Per-
centages greater than 254 shall be
represented as 255. This value shall be
updated once per power-on hour (when the
controller is not in a sleep state).
32
16
Data Units Read (in LBAs)
Contains the number of 512 byte data units
the host has read from the controller; this value
does not include metadata. This value is
reported in thousands (i.e., a value of 1 corre-
sponds to 1000 units of 512 bytes read) and is
rounded up. When the LBA size is a value other
than 512 bytes, the
controller shall convert the amount of data
read to 512-byte units.
48
16
Data Units Write (in LBAs)
Contains the number of 512 byte data units
the host has written to the controller; this value
does not include metadata. This value is
reported in thousands (i.e., a value of 1 corre-
sponds to 1000 units of 512 bytes
written) and is rounded up. When the LBA size
is a value other than 512 bytes, the controller
shall convert the amount of data written to
512-byte units. For the NVM* command set,
logical blocks written as part of Write opera-
tions shall be included in this value. Write
Uncorrectable commands shall not impact this
value.
64
16
Host Read Commands
Contains the number of read commands
issued to the controller.
80
16
Host Write Commands
Contains the number of write commands
issued to the controller.
