====== Self-Monitoring, Analysis and Reporting Technology ======
//also called SMART or S.M.A.R.T.//

You should do a SMART test on all your [[:hardware:hdd|HDDs]] and [[:hardware:ssd|SSDs]] before you put any data on it and save the values somewhere for later comparison.

===== Interpretation =====

| 5 ^ Reallocated sector count | The sectors which are reallocated to another place on the disk. On HDDs, this might mean that they fail very soon. |
| 192 ^ Power-off retract count | Instances where the drive didn’t properly shut down or lost power unexpectedly. Happens when you "pull the plug", may also happen when you hot plug HDDs which aren't hot-pluggable. |
| 197 ^ Currently pending sectors | The sectors which are reallocated due to errors reading them. A sign for a failing HDD, whereas reallocation in SSDs is common as some cells fail earlier than others. |

==== HDDs ====
Hard disk drives usually report **pending sectors** or **reallocated sectors** before they fail. As soon as you see the number go up, you should [[:admin:backup:|back up]] the most important files first. Monitor SMART data while you do this.

| 3 ^ Spin-up time | The time in milliseconds the drive took to bring the platters up to the correct speed (usualls 5200, 5400 or 7200 1/min). If the number is more than 500 higher than where you got the drive, the motor might be failing. |

==== SSDs ====
Don't trust any metric as indicator for failure on SSDs as they can die spontaneously, even more so than HDDs can.

| 241 ^ Lifetime Writes in GiB | The amount of data in GiB written to the drives. If that's higher than the TBW[(tbw>//Total Bytes Written// or //TeraBytes Written//, found in the spec sheet of the drive, usually between 100TiB and 300TiB)] specification for the SSD, failure might be imminent. |

===== Tools =====
==== Windows ====
^ Crystal Disk Info | graphical application to view SMART data |

==== Linux ====
^ gsmartcontrol | graphical application to view SMART data |
^ smartctl | CLI tool from the smartmontools suite |

===== further information =====
  * [[https://de.wikipedia.org/wiki/Self-Monitoring,_Analysis_and_Reporting_Technology|Wikipedia: SMART]]