SMART Decoder

Reads the output of smartctl -a or smartctl -x and turns it into a straight answer: HEALTHY, WATCH, or FAILING, with the reasoning spelled out. It handles ATA and SATA attribute tables in both the standard and the brief column layouts, and NVMe health logs. Every critical attribute that is off its healthy reading gets a plain-English line, so you learn what reallocated sectors, pending sectors, CRC errors, and NVMe critical warnings actually mean. It also works out power on time in years, SSD wear, and total terabytes written.

Run smartctl -a /dev/sda (or smartctl -a /dev/nvme0) as root, copy the whole output, and paste it in. Leave Detail on "Verdict and findings" for the summary, or switch to "Full attribute list" to see every attribute the drive reported with an explanation of each one. Re-run the check every few weeks and compare, because a single snapshot cannot show whether a count is growing.

The usual routine is posting a screenshot to a forum and waiting a day for someone to tell you whether 8 reallocated sectors matter. Vendor tools go the other way and hide the raw values behind a green tick. This page explains every attribute, tells you when a scary looking number is really a loose SATA cable, and does it in your browser: only the text report you paste is read, and your files and inputs never leave your device.

Which SMART attributes actually predict failure?

The ones worth acting on are 5 Reallocated_Sector_Ct, 187 Reported_Uncorrect, 188 Command_Timeout, 197 Current_Pending_Sector, and 198 Offline_Uncorrectable. On NVMe it is the critical warning bitmask, media and data integrity errors, and available spare falling to its threshold. Most other attributes are workload counters or vendor scaled numbers that mean nothing in isolation.

What does one reallocated sector mean?

One sector went bad and the drive quietly swapped in a spare. A count of 1 that never changes is not a reason to replace a drive, and plenty of drives run for years like that. What matters is the trend: check again in a week, and if the number is climbing, move your data off and replace the drive. Pending sectors (attribute 197) are different, because those are unreadable right now.

Is my drive data uploaded anywhere?

No. Only the text report you paste is read, and your files and inputs never leave your device. The decoding runs in your browser, and the page keeps working offline after the first load. Serial numbers stay in the text you pasted, so nothing identifying is sent anywhere.