As a newbie to the group I apologize if this has been covered before, but I have not found any discussion elsewhere.
We are using ZFS with single disk drives to make an offline backup copy of a large data(~300 TB) set that we have on a FreeNAS RAID. Previously we successfully copied ~120 TB to ~30 4-TB drives. We copy the data to the drive with rsync and then the scrub the volume to verify it.
Since updating to 1.8.1 performance has decreased dramatically. Copies are slower, the scrub is slower, and the entire Mac suffers stalls of 10 to 30 seconds during which no applications respond. Sorry, I don't remember which version we upgraded from (1.6 or 1.7 I expect).
Hardware: Late 2015 iMac, 4 GHz Core i7, 32 GB RAM, external OWC USB3 drive toaster.
Software: High Sierra, 10.13.6.
Memory usage is high (18 - 20 GB wired), but memory pressure does not seem to be a problem.
I am considering downgrading to an earlier version. Before I do that, does anyone have other suggestions?
Thanks, Ken