Disks accessed every few seconds

Hi,

I am configuring my first non-virtual FreeNAS system (FreeNAS-9.2.1.6-RELEASE-x64, Intel i3-4350, 16GB ECC memory).

I created a RaidZ2 volume out of four 4TB SATA disks. Under the volume I created a few ZFS Datasets. I configured and tested email reports. Then I configured and started CIFS and UPS services.

After which I noticed that all four of the disks are being accessed every minute and a half, or so, with a short burst. That happens even when I am not logged in to the...

Disks accessed every few seconds