Provided by: libnvme-dev_1.8-3ubuntu1_amd64 
NAME
struct nvme_smart_log - SMART / Health Information Log (Log Identifier 02h)
SYNOPSIS
struct nvme_smart_log {
__u8 critical_warning;
__u8 temperature[2];
__u8 avail_spare;
__u8 spare_thresh;
__u8 percent_used;
__u8 endu_grp_crit_warn_sumry;
__u8 rsvd7[25];
__u8 data_units_read[16];
__u8 data_units_written[16];
__u8 host_reads[16];
__u8 host_writes[16];
__u8 ctrl_busy_time[16];
__u8 power_cycles[16];
__u8 power_on_hours[16];
__u8 unsafe_shutdowns[16];
__u8 media_errors[16];
__u8 num_err_log_entries[16];
__le32 warning_temp_time;
__le32 critical_comp_time;
__le16 temp_sensor[8];
__le32 thm_temp1_trans_count;
__le32 thm_temp2_trans_count;
__le32 thm_temp1_total_time;
__le32 thm_temp2_total_time;
__u8 rsvd232[280];
};
Members
critical_warning
This field indicates critical warnings for the state of the controller. Critical warnings may
result in an asynchronous event notification to the host. Bits in this field represent the
current associated state and are not persistent (see enum nvme_smart_crit).
temperature Composite Temperature: Contains a value corresponding to a temperature in Kelvins that
represents the current composite temperature of the controller and namespace(s) associated
with that controller. The manner in which this value is computed is implementation specific
and may not represent the actual temperature of any physical point in the NVM subsystem.
Warning and critical overheating composite temperature threshold values are reported by the
WCTEMP and CCTEMP fields in the Identify Controller data structure.
avail_spare Available Spare: Contains a normalized percentage (0% to 100%) of the remaining spare
capacity available.
spare_thresh
Available Spare Threshold: When the Available Spare falls below the threshold indicated in
this field, an asynchronous event completion may occur. The value is indicated as a
normalized percentage (0% to 100%). The values 101 to 255 are reserved.
percent_used
Percentage Used: Contains a vendor specific estimate of the percentage of NVM subsystem life
used based on the actual usage and the manufacturer's prediction of NVM life. A value of 100
indicates that the estimated endurance of the NVM in the NVM subsystem has been consumed, but
may not indicate an NVM subsystem failure. The value is allowed to exceed 100. Percentages
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).
endu_grp_crit_warn_sumry
Endurance Group Critical Warning Summary: This field indicates critical warnings for the
state of Endurance Groups. Bits in this field represent the current associated state and are
not persistent (see enum nvme_smart_egcw).
rsvd7 Reserved
data_units_read
Data Units Read: 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 corresponds to 1000 units of 512 bytes read) and is rounded up (e.g., one
indicates the that number of 512 byte data units read is from 1 to 1000, three indicates that
the number of 512 byte data units read is from 2001 to 3000). When the LBA size is a value
other than 512 bytes, the controller shall convert the amount of data read to 512 byte units.
For the NVM command set, logical blocks read as part of Compare, Read, and Verify operations
shall be included in this value. A value of 0h in this field indicates that the number of
Data Units Read is not reported.
data_units_written
Data Units Written: 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 corresponds to 1000 units of 512 bytes written) and is rounded up (e.g., one
indicates that the number of 512 byte data units written is from 1 to 1,000, three indicates
that the number of 512 byte data units written is from 2001 to 3000). 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 operations shall
be included in this value. Write Uncorrectable commands and Write Zeroes commands shall not
impact this value. A value of 0h in this field indicates that the number of Data Units
Written is not reported.
host_reads Host Read Commands: Contains the number of read commands completed by the controller. For the
NVM command set, this value is the sum of the number of Compare commands and the number of
Read commands.
host_writes Host Write Commands: Contains the number of write commands completed by the controller. For
the NVM command set, this is the number of Write commands.
ctrl_busy_time
Controller Busy Time: Contains the amount of time the controller is busy with I/O commands.
The controller is busy when there is a command outstanding to an I/O Queue (specifically, a
command was issued via an I/O Submission Queue Tail doorbell write and the corresponding
completion queue entry has not been posted yet to the associated I/O Completion Queue). This
value is reported in minutes.
power_cycles
Power Cycles: Contains the number of power cycles.
power_on_hours
Power On Hours: Contains the number of power-on hours. This may not include time that the
controller was powered and in a non-operational power state.
unsafe_shutdowns
Unsafe Shutdowns: Contains the number of unsafe shutdowns. This count is incremented when a
Shutdown Notification (CC.SHN) is not received prior to loss of power.
media_errors
Media and Data Integrity Errors: Contains the number of occurrences where the controller
detected an unrecovered data integrity error. Errors such as uncorrectable ECC, CRC checksum
failure, or LBA tag mismatch are included in this field. Errors introduced as a result of a
Write Uncorrectable command may or may not be included in this field.
num_err_log_entries
Number of Error Information Log Entries: Contains the number of Error Information log entries
over the life of the controller.
warning_temp_time
Warning Composite Temperature Time: Contains the amount of time in minutes that the
controller is operational and the Composite Temperature is greater than or equal to the
Warning Composite Temperature Threshold (WCTEMP) field and less than the Critical Composite
Temperature Threshold (CCTEMP) field in the Identify Controller data structure. If the value
of the WCTEMP or CCTEMP field is 0h, then this field is always cleared to 0h regardless of
the Composite Temperature value.
critical_comp_time
Critical Composite Temperature Time: Contains the amount of time in minutes that the
controller is operational and the Composite Temperature is greater than or equal to the
Critical Composite Temperature Threshold (CCTEMP) field in the Identify Controller data
structure. If the value of the CCTEMP field is 0h, then this field is always cleared to 0h
regardless of the Composite Temperature value.
temp_sensor Temperature Sensor 1-8: Contains the current temperature in degrees Kelvin reported by
temperature sensors 1-8. The physical point in the NVM subsystem whose temperature is
reported by the temperature sensor and the temperature accuracy is implementation specific.
An implementation that does not implement the temperature sensor reports a value of 0h.
thm_temp1_trans_count
Thermal Management Temperature 1 Transition Count: Contains the number of times the
controller transitioned to lower power active power states or performed vendor specific
thermal management actions while minimizing the impact on performance in order to attempt to
reduce the Composite Temperature because of the host controlled thermal management feature
(i.e., the Composite Temperature rose above the Thermal Management Temperature 1). This
counter shall not wrap once the value FFFFFFFFh is reached. A value of 0h, indicates that
this transition has never occurred or this field is not implemented.
thm_temp2_trans_count
Thermal Management Temperature 2 Transition Count
thm_temp1_total_time
Total Time For Thermal Management Temperature 1: Contains the number of seconds that the
controller had transitioned to lower power active power states or performed vendor specific
thermal management actions while minimizing the impact on performance in order to attempt to
reduce the Composite Temperature because of the host controlled thermal management feature.
This counter shall not wrap once the value FFFFFFFFh is reached. A value of 0h, indicates
that this transition has never occurred or this field is not implemented.
thm_temp2_total_time
Total Time For Thermal Management Temperature 2
rsvd232 Reserved
February 2025 struct nvme_smart_log libnvme(2)