| Hard Drive |
A high-capacity, self-contained storage device containing a read-write mechanism plus one or more hard disks, inside a sealed unit. Also called hard disk drive. |
Backblaze implements several different models of hard drives with varying capacities. |
| Reliability |
A hard drive classified as having low reliablity is a hard drive that fails before the early failure cutoff of 2.6 years old. A hard drive classified as having high reliability is a hard drive that does not fail before the early faliure cutoff. |
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| Failure |
Contains a “0” if the drive is active. Contains a “1” if this is the last day the drive was operational before failing. |
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| Early Failure |
A failure which occurs in a hard drive where age in years is less than 2.6 years old, contains a "1" if the drive is an early failure. |
Calculated drive age in years from the feature (SMART_9: Power-On-Hours) / 365 / 24 |
| SMART Attributes |
SMART (Self-Monitoring, Analysis and Reporting Technology) is a monitoring system included in hard drives used to detect and report various indicators of drive reliability with the intent of anticipating imminent hardware failures. |
There are several SMART attributes in the data. Detailed information on each attribute can be found in our smart_attributes_index.md |
| Serial Number |
The manufacturer-assigned serial number of the drive. |
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| Model |
The manufacturer-assigned model number of the drive. |
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| Manufacturer |
The manufacturer/company that built the hard drive. The manufacturer information is derived from the model number through additional research. |
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| Capacity Terabytes |
The drive capacity (amount of storage) measured in bytes. |
Converted bytes to terabytes using the following calculation: capacity_bytes / 1,000,000,000,000 |
| Uncorrectable Sector Count |
The total count of uncorrectable errors when reading/writing a sector. A rise in the value of this attribute indicates defects of the disk surface and/or problems in the mechanical subsystem. |
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| Current Pending Sector Count |
Count of "unstable" sectors (waiting to be remapped, because of unrecoverable read errors). If an unstable sector is subsequently read successfully, the sector is remapped and this value is decreased. |
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| Command Timeout |
The count of aborted operations due to HDD timeout. Normally this attribute value should be equal to zero. |
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| Reported Uncorrectable Errors |
The count of errors that could not be recovered using hardware ECC. |
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| Reallocated Sectors Count |
The raw value represents a count of the bad sectors that have been found and remapped. |
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| Drive Age In Years |
Numeric value in years of a hard drive's age |
Calculated drive age in years using the feature (SMART_9: Power-On-Hours) / 365 / 24 |