Full SMART Metrics for Hard Disk

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Metrics Table

ID	Attribute Name	Description
1	Read Error Rate	Frequency of errors during read operations.
2	Throughput Performance	Overall performance of a device.
3	Spin-Up Time	Time required for a spindle to spin up to operational speed. Not used with an SSD, as an SSD has no moving parts.
4	Start/Stop Count	Estimated remaining life, based on the number of spin-up/spin-down cycles. Counts down from 100 to 0. Raw value holds the actual number of cycles.
5	Reallocated Sectors Count	Number of unused spare sectors. On encountering a read/write/check error, a device remaps a bad sector to a "healthy" one from a reserve pool. Normalized value decreases as available spares decrease. Raw value indicates the number of remapped sectors on a regular hard drive and the number of failed flash memory blocks on an SSD.
6	Read Channel Margin	No reliable information available.
7	Seek Error Rate	Frequency of errors during disk head positioning.
8	Seek Time Performance	Characterizes performance of mechanical seeks of a disk head. Not used by an SSD.
9	Power-On Hours Count	Estimated remaining lifetime, based on the time a device was powered on. Normalized value decreases over time from 100 to 0. Raw value shows the actual powered-on time, usually in hours.
10	Spin-up Retries	Raw value shows the number of unsuccessful attempts to spin a spindle up to operational speed. Critical for rotational drives. Not used by SSDs.
11	Calibration Retries	Raw value typically stores the number of unsuccessful read head and positioning system calibrations.
12	Power Cycle Count	Estimated remaining life, based on the number of power on/off cycles. Counts down from 100 to 0. Raw value holds the actual number of power cycles.
13	Soft Read Error Rate	Uncertainty about the meaning. Some documentation quotes this as the number of errors not corrected by ECC and reported to the host controller, while others say it's the number of errors corrected by ECC.
100	Erase/Program Cycles	Total count of erase/program cycles for entire flash memory in its lifetime. SSDs have a limit on how many times one can write to them. The exact values depend on the type and make of the flash memory chip.
103	Translation Table Rebuild	Number of events when internal tables of block addresses were damaged and rebuilt. Raw value indicates the actual event count.
108	Unknown (108)	No reliable information available.
170	Reserved Block Count	On an SSD, describes the state of the reserve block pool. Attribute value shows the percentage of the pool remaining. Raw value sometimes contains the actual number of used reserve blocks.
171	Program Fail Count	Number of times a write to flash memory failed. When flash memory is worn out, it cannot be written to any longer and becomes read-only. Raw value shows the actual number of failures.
172	Erase Fail Count	Number of times an erase operation on flash memory failed. The complete write cycle of flash memory consists of two stages: erasing and recording ("programming") data. When flash memory is worn out, it cannot be written to any longer and becomes read-only. Raw value shows the actual number of failures.
173	Wear Leveller Worst Case Erase Count	Maximum number of erase operations performed on a single flash memory block.
174	Unexpected Power Loss	Number of unexpected power outages before a command to turn off the disk is received. Lifetime with respect to such shutdowns is much less than in case of normal shutdown for hard drives. On an SSD, there is a risk of losing the internal state table when an unexpected shutdown occurs.
175	Program Fail Count	Number of times a write to flash memory failed. When flash memory is worn out, it cannot be written to any longer and becomes read-only. Raw value shows the actual number of failures.
176	Erase Fail Count	Number of times an erase operation on flash memory failed. Complete write cycle of flash memory consists of erasing and recording data. When flash memory is worn out, it becomes read-only. Raw value shows the actual number of failures.
177	Wear Leveling Count	Maximum number of erase operations performed on a single flash memory block.
178	Used Reserved Block Count	On an SSD, describes the state of the reserve block pool. Attribute value shows the percentage of the pool remaining. Raw value sometimes contains the actual number of used reserve blocks.
179	Used Reserved Block Count	On an SSD, describes the state of the reserve block pool. Attribute value shows the percentage of the pool remaining. Raw value sometimes contains the actual number of used reserve blocks.
180	Unused Reserved Block Count	On SSDs, describes the state of the reserve block pool. Attribute value shows the percentage of the pool remaining. Raw value sometimes contains the actual number of unused reserve blocks.
181	Program Fail Count	Number of times a write to flash memory failed. When flash memory is worn out, it becomes read-only. Raw value shows the actual number of failures.
182	Erase Fail Count	Number of times an erase operation on flash memory failed. Complete write cycle of flash memory consists of erasing and recording data. When flash memory is worn out, it becomes read-only. Raw value shows the actual number of failures.
183	SATA Downshifts	Indicates how often it was necessary to decrease SATA transmission speed (e.g., from 6 Gbps to 3 or 1.5 Gbps) to transfer data successfully. If attribute value is decreasing, try replacing the SATA cable.
184	End-to-End error	Number of data corruption occurrences in the internal disk cache. Malfunctions of the cache memory indicated by this attribute are critical to proper operation.
185	Head Stability	No reliable information available.
186	Induced Op-Vibration Detection	No reliable information available.
187	Reported Uncorrectable Errors	Number of UNC errors, i.e., read errors which Error Correction Code (ECC) failed to recover.
188	Command Timeout	Number of operations interrupted due to HDD timeout.
189	High Fly Writes	Number of write errors caused by the write head being outside the normal range of height above the disk platter.
190	Temperature	Temperature monitored by a sensor inside the drive. Raw value typically holds the actual temperature (hexadecimal) in its rightmost two digits.
191	G-Sense Errors	Indicates how many times a disk stopped working due to shock or vibration. Typically used in laptop hard drives. In desktop hard drives, the attribute is sometimes listed but never changes, as vibration detection circuitry might not be available.
192	Power-Off Retract Cycles	Number of unexpected power outages before a command to turn off the disk is received. Lifetime with respect to such shutdowns is much less than in case of normal shutdown for hard drives. On an SSD, there is a risk of losing the internal state table during an unexpected shutdown.
193	Load/Unload Cycles	Number of head movement cycles between the data zone and the head parking area or a dedicated unload ramp. Counts down from 100 to 0. Raw value typically holds the actual number of cycles.
194	Temperature	Temperature monitored by a sensor inside the drive. Raw value typically holds the actual temperature (hexadecimal) in its rightmost two digits.
195	Hardware ECC Recovered	Number of errors corrected using Error Correction Code.
196	Reallocation Events	Total number of reallocation events, including both off-line reallocations and reallocations during actual write operations.
197	Current Pending Sectors	Number of unstable sectors waiting to be re-tested and possibly remapped.
198	Off-line Uncorrectable	Number of bad sectors detected during offline scan of a disk. When idling, a modern disk tests itself to detect possible defects in rarely used surface areas.
199	UDMA CRC Error Rate	Number of errors occurring when transferring data via a cable between a disk and a motherboard port. If the value decreases, try replacing the ATA cable. On Parallel ATA drives, avoid "round" cables.
200	Write Error Rate	Rate of errors during write.
201	Soft Read Errors	Uncertainty about the meaning. Some documentation quotes this as the number of errors not corrected by ECC and reported to the host controller, while others say it's the number of errors corrected by ECC.
202	Data Address Mark Errors	Number of errors encountered when a read head searches for a requested sector.
203	Run Out Cancel	Number of errors caused by incorrect checksum during error correction.
204	Soft ECC Corrections	Number of errors corrected using Error Correction Code.
205	Thermal Asperity Rate	Rate of read errors due to short-term temperature fluctuations on a hard drive read head.
206	Flying Height	Deviation of a head height above the disk surface from the optimal height value. Too close risks mechanical damage; too far causes read/write errors.
207	Spin High Current	Amount of current needed to spin a hard disk up. Only used in rotational hard drives.
209	Offline Seek Performance	Characterizes performance of seek operations of a disk head measured during an offline scan.
220	Disk Shift	Distance the disk has shifted in relation to the theoretical spindle axis due to mechanical damage or overheating.
221	G-Sense Error Rate	Indicates how many times a disk stopped working due to shock or vibration. Typically used in laptop hard drives. In desktop hard drives, the attribute is sometimes listed but never changes, as vibration detection circuitry might not be available.
222	Loaded Hours	Time a disk head spent in the data zone, rather than in the parking area or on a head ramp. Counts down from 100 to 0. Raw value often holds the actual number of hours.
223	Load/Unload Retries	Number of failures when moving a head from the data area to the parking area and vice versa.
224	Load Friction	Friction associated with moving a head between the data area and the parking area, especially for disks with dedicated unload ramp.
225	Load/Unload Cycles	Number of head movement cycles between the data zone and the head parking area or a dedicated unload ramp. Counts down from 100 to 0. Raw value typically holds the actual number of cycles.
226	Load-in Time	Time a disk head spent in the data zone, rather than in the parking area or on a head ramp. Counts down from 100 to 0. Raw value often holds the actual number of hours.
227	Torque Amplification Count	Indicates how many times high current was required to spin a hard disk up or maintain rotational speed.
228	Power-Off Retracts	Number of unexpected power outages before a command to turn off the disk is received. Lifetime with respect to such shutdowns is much less than in case of normal shutdown for hard drives. On an SSD, there is a risk of losing the internal state table during an unexpected shutdown.
230	GMR Head Amplitude	Amplitude of disk head oscillations.
231	Temperature	Temperature monitored by a sensor inside the drive. Raw value typically holds the actual temperature (hexadecimal) in its rightmost two digits.
232	Available Reserved Space	Attribute used in SSDs to denote the remaining reserved space. Counts down from 100 to 0. Raw value is vendor-specific.
233	Media Wearout Indicator	Remaining flash memory life (on an SSD).
240	Head Flying Hours	Time a disk head spent in the data zone, rather than in the parking area or on a head ramp. Counts down from 100 to 0. Raw value often holds the actual number of hours.
241	Total LBAs Written	Total number of 512-byte sectors written during the entire lifetime of the device.
242	Total LBAs Read	Total number of 512-byte sectors read during the entire lifetime of the device.
250	Read Error Retry Rate	No reliable information available.

Description of Selected Metrics

1 - Raw Read Error Rate

This metric quantifies the rate at which the hard drive encounters errors when reading data from the disk surface. It’s an indicator of the physical condition of the disk, where a higher value may suggest a deterioration in disk quality, potentially leading to data loss.

5 - Reallocated Sectors Count

This count reflects the number of sectors on the disk that have been identified as defective and subsequently replaced with spare sectors from the reserve pool. Frequent reallocations can be a precursor to drive failure, as they indicate significant wear or damage to the disk surface.

7 - Seek Error Rate

This rate measures the frequency of errors encountered by the drive's head when trying to reach a specific area of the disk. These errors are often due to mechanical failures within the drive’s moving components or external shocks and vibrations affecting the drive's precise operations.

9 - Power-On Hours

This value records the cumulative number of hours the hard drive has been active. It is used to estimate the age of the drive and assess its wear level, helping predict end-of-life by comparing against typical lifespan estimates for the drive model.

12 - Power Cycle Count

This count logs the number of times the hard drive has been powered up and down. Frequent power cycles can stress the mechanical components of the drive, especially the spindle motor and bearings, reducing the overall lifespan of the device.

183 - SATA Downshift Error Count

This metric tracks the number of times the SATA interface has downshifted from a higher to a lower speed due to errors in data transmission. Persistent errors in downshifting can indicate issues with either the drive’s controller or the SATA cable quality.

184 - End-to-End Error

This error count monitors the data integrity as data is transferred internally between the drive's buffer and its host. Errors here can imply issues with the drive's internal processing or hardware malfunctions that could compromise data integrity.

187 - Reported Uncorrectable Errors

This feature logs the number of errors that could not be fixed using the hardware's error-correcting code. It’s a critical measure of a drive’s ability to maintain data integrity, with high values suggesting a risk of data loss.

193 - Load Cycle Count

This count tracks how often the drive's heads are loaded into the read/write position. Excessive loading and unloading can accelerate wear on the head and the drive medium, potentially leading to drive failure.

197 - Current Pending Sectors Count

This value reports the number of unstable sectors that have yet to be reallocated. Sectors awaiting reallocation can cause data read/write errors and may eventually be marked as bad, affecting data retrieval and overall system performance.

198 - Offline Uncorrectable Sectors Count

This count reflects the number of sectors that failed during offline operations (such as during more intensive scans) and could not be corrected. It indicates problems with the disk surface or with the read/write heads.

199 - UltraDMA CRC Error Rate

This measures the frequency of cyclic redundancy check (CRC) errors during Ultra DMA mode. These errors are usually due to problems with the drive interface or data cable issues and can significantly affect data transfer reliability and speed.