"chunk" sound every 5 seconds

[Jos Chrispijn]

Just to let you know that I had the same experience with my pve raid 1 
setup (2x WD Red Pro).
With interest I read several topics about it (zfs_txg_timeout option) in 
this very informative forum.
We found out that my zfs pool was damaged (drives are ok), thus 
generating this behavior as well.
Now that we have repaired this, there is no chunk sound active any more.

Just thinking with you (pve nub online ;-)
Jos Chrispijn