Question: In order to do disk rotation in a server, I need to know the current running time (online) time of a disk on a Linux CentOS release 6.3 (Final) system.

The disks are connected with SATA (e.g. /dev/sdc), are simple rotating type (Western Digital RE type disks), and are not organized in any RAID or similar.

I have tried to find it using smartctrl (as suggested in superuser.com/questions/279412), but was unable to find the information. ?Any suggestion for command ?

Answer: Answer based on comments from @Zoredache:

Command is smartctl –all /dev/sdc and the section to look under is “Vendor Specific SMART Attributes with Thresholds”, which has an attribute named “Power_On_Hours”.

So command for just getting power on hours (runnning) is:

smartctl –all /dev/sdc | grep Power_On_Hours

Which can then show something like:

9 Power_On_Hours ?0x0032 ?087 ?087 ?000 ?Old_age ?Always ?- ?10171

The running time is thus: 10171 hours