What is my NAS doing? Strange HDD activity

[fostersimported]

All,
From 0200 this morning my HDDs are read/writing. They are doing something, I cannot work out what it is.
Very unusual activity.

I initially thought it was my cloud backup as that runs every Sunday, or Emby generating Thumb Nails.

I have shut down all Jails and services, System Data Set is on SSD.

As you can see CPU load is at 25%

I installed the update 11.3-U2.1 and rebooted, shut down all Jails and services and the load remains, normally at idle I see 1%

Disconnected Network Cable and Monitored processes through Console

How can i find out what is going on ???

 

[sretalla]

Could it be a scrub or Long SMART test?

Look at the schedule under the Tasks in the GUI.

Also look at the output of zpool status

 

[fostersimported]

ok, Thanks,
it is a Scrub, usually, they have completed by now.

Thanks