nvme-wdc-smart-add-log(1) Manual Page

1

Most recent five (5) minute accumulated set.

2-12

Previous five (5) minute accumulated sets.

13

The accumulated total of sets 1 through 12 that contain the previous hour of accumulated statistics.

14

The statistical set accumulated since power-up.

15

The statistical set accumulated during the entire lifetime of the device.

Physical NAND bytes written.

The number of bytes written to NAND. 16 bytes - hi/lo

Physical NAND bytes read

The number of bytes read from NAND. 16 bytes - hi/lo

Bad NAND Block Count

Raw and normalized count of the number of NAND blocks that have been retired after the drives manufacturing tests (i.e. grown back blocks). 2 bytes normalized, 6 bytes raw count

Uncorrectable Read Error Count

Total count of NAND reads that were not correctable by read retries, all levels of ECC, or XOR (as applicable). 8 bytes

Soft ECC Error Count

Total count of NAND reads that were not correctable by read retries, or first-level ECC. 8 bytes

SSD End to End Detection Count

A count of the detected errors by the SSD end to end error correction which includes DRAM, SRAM, or other storage element ECC/CRC protection mechanism (not NAND ECC). 4 bytes

SSD End to End Correction Count

A count of the corrected errors by the SSD end to end error correction which includes DRAM, SRAM, or other storage element ECC/CRC protection mechanism (not NAND ECC). 4 bytes

System Data % Used

A normalized cumulative count of the number of erase cycles per block since leaving the factory for the system (FW and metadata) area. Starts at 0 and increments. 100 indicates that the estimated endurance has been consumed.

User Data Max Erase Count

The maximum erase count across all NAND blocks in the drive. 4 bytes

User Data Min Erase Count

The minimum erase count across all NAND blocks in the drive. 4 bytes

Refresh Count

A count of the number of blocks that have been re-allocated due to background operations only. 8 bytes

Program Fail Count

Raw and normalized count of total program failures. Normalized count starts at 100 and shows the percent of remaining allowable failures. 2 bytes normalized, 6 bytes raw count

User Data Erase Fail Count

Raw and normalized count of total erase failures in the user area. Normalized count starts at 100 and shows the percent of remaining allowable failures. 2 bytes normalized, 6 bytes raw count

System Area Erase Fail Count

Raw and normalized count of total erase failures in the system area. Normalized count starts at 100 and shows the percent of remaining allowable failures. 2 bytes normalized, 6 bytes raw count

Thermal Throttling Status

The current status of thermal throttling (enabled or disabled). 2 bytes

Thermal Throttling Count

A count of the number of thermal throttling events. 2 bytes

PCIe Correctable Error Count

Summation counter of all PCIe correctable errors (Bad TLP, Bad DLLP, Receiver error, Replay timeouts, Replay rollovers). 8 bytes

Host Read Commands

Number of host read commands received during the reporting period.

Host Read Blocks

Number of 512-byte blocks requested during the reporting period.

Average Read Size

Average Read size is calculated using (Host Read Blocks/Host Read Commands).

Host Read Cache Hit Commands

Number of host read commands that serviced entirely from the on-board read cache during the reporting period. No access to the NAND flash memory was required. This count is only updated if the entire command was serviced from the cache memory.

Host Read Cache Hit Percentage

Percentage of host read commands satisfied from the cache.

Host Read Cache Hit Blocks

Number of 512-byte blocks of data that have been returned for Host Read Cache Hit Commands during the reporting period. This count is only updated with the blocks returned for host read commands that were serviced entirely from cache memory.

Average Read Cache Hit Size

Average size of read commands satisfied from the cache.

Host Read Commands Stalled

Number of host read commands that were stalled due to a lack of resources within the SSD during the reporting period (NAND flash command queue full, low cache page count, cache page contention, etc.). Commands are not considered stalled if the only reason for the delay was waiting for the data to be physically read from the NAND flash. It is normal to expect this count to equal zero on heavily utilized systems.

Host Read Commands Stalled Percentage

Percentage of read commands that were stalled. If the figure is consistently high, then consideration should be given to spreading the data across multiple SSDs.

Host Write Commands

Number of host write commands received during the reporting period.

Host Write Blocks

Number of 512-byte blocks written during the reporting period.

Average Write Size

Average Write size calculated using (Host Write Blocks/Host Write Commands).

Host Write Odd Start Commands

Number of host write commands that started on a non-aligned boundary during the reporting period. The size of the boundary alignment is normally 4K; therefore this returns the number of commands that started on a non-4K aligned boundary. The SSD requires slightly more time to process non-aligned write commands than it does to process aligned write commands.

Host Write Odd Start Commands Percentage

Percentage of host write commands that started on a non-aligned boundary. If this figure is equal to or near 100%, and the NAND Read Before Write value is also high, then the user should investigate the possibility of offsetting the file system. For Microsoft Windows systems, the user can use Diskpart. For Unix-based operating systems, there is normally a method whereby file system partitions can be placed where required.

Host Write Odd End Commands

Number of host write commands that ended on a non-aligned boundary during the reporting period. The size of the boundary alignment is normally 4K; therefore this returns the number of commands that ended on a non-4K aligned boundary.

Host Write Odd End Commands Percentage

Percentage of host write commands that ended on a non-aligned boundary.

Host Write Commands Stalled

Number of host write commands that were stalled due to a lack of resources within the SSD during the reporting period. The most likely cause is that the write data was being received faster than it could be saved to the NAND flash memory. If there was a large volume of read commands being processed simultaneously, then other causes might include the NAND flash command queue being full, low cache page count, or cache page contention, etc. It is normal to expect this count to be non-zero on heavily utilized systems.

Host Write Commands Stalled Percentage

Percentage of write commands that were stalled. If the figure is consistently high, then consideration should be given to spreading the data across multiple SSDs.

NAND Read Commands

Number of read commands issued to the NAND devices during the reporting period. This figure will normally be much higher than the host read commands figure, as the data needed to satisfy a single host read command may be spread across several NAND flash devices.

NAND Read Blocks

Number of 512-byte blocks requested from NAND flash devices during the reporting period. This figure would normally be about the same as the host read blocks figure

Average NAND Read Size

Average size of NAND read commands.

NAND Write Commands

Number of write commands issued to the NAND devices during the reporting period. There is no real correlation between the number of host write commands issued and the number of NAND Write Commands.

NAND Write Blocks

Number of 512-byte blocks written to the NAND flash devices during the reporting period. This figure would normally be about the same as the host write blocks figure.

Average NAND Write Size

Average size of NAND write commands. This figure should never be greater than 128K, as this is the maximum size write that is ever issued to a NAND device.

NAND Read Before Write

This is the number of read before write operations that were required to process non-aligned host write commands during the reporting period. See Host Write Odd Start Commands and Host Write Odd End Commands. NAND Read Before Write operations have a detrimental effect on the overall performance of the device.