This is the mail from my FREENAS system during the first of three resilvering (the one that took over 24 hours to complete) operations.
Checking status of zfs pools:
NAME SIZE ALLOC FREE EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
freenas-boot 7.25G 1.02G 6.23G - - 14% 1.00x ONLINE -
vol1 8.12T 6.29T 1.84T - - 77% 1.00x ONLINE /mnt
pool: vol1
state: ONLINE
status: One or more devices is currently being resilvered. The pool will
continue to function, possibly in a degraded state.
action: Wait for the resilver to complete.
scan: resilver in progress since Mon Sep 7 13:56:52 2015
3.26T scanned out of 6.29T at 72.8M/s, 12h5m to go
557G resilvered, 51.94% done
config:
NAME STATE READ WRITE CKSUM
vol1 ONLINE 0 0 0
raidz2-0 ONLINE 0 0 0
gptid/52e7ec24-ccae-11e2-b844-50e54944e369 ONLINE 0 0 0
gptid/534a6b30-ccae-11e2-b844-50e54944e369 ONLINE 0 0 0
gptid/53a2547b-ccae-11e2-b844-50e54944e369 ONLINE 0 0 0
gptid/542787c7-ccae-11e2-b844-50e54944e369 ONLINE 0 0 0
gptid/2b1341f8-5592-11e5-9524-0cc47a0deacf ONLINE 0 0 0 (resilvering)
gptid/554a8e86-ccae-11e2-b844-50e54944e369 ONLINE 0 0 0
errors: No known data errors