ZFS resilvering drive on an ONLINE and healthy pool

[Chris Stankevitz]

Hello,

I recently imported an 11 drive RAIDZ3 pool.  For some reason, one of 
the disks was unavailable (let's assume I didn't have it fully seated 
when I inserted it).

Upon import, the pool was degraded with a missing disk (as expected).  I 
exported the pool within ~10 seconds of importing it.  Nothing should 
have attempted to read or write to the pool except for zfs itself. 
Actually all ZFS filesystem in the pool are readonly (it is used for 
backup).

I reseated the drive and imported again.  Now I see the status below. 
Note that:

1. The pool is ONLINE

2. All 11 drives are ONLINE

3. Apparently a resilver is in progress

4. The resilver is progressing at "1/s" (whatever that means).

Can anyone tell me what is going on?  I assume that a mini-resilver took 
place because one of the drives was unavailable for ~10 seconds, but I 
would imaging that this would have completed rather quickly.

Thank you,

Chris

===

root at silver:/agp0/admin/scripts # zpool status agb0
   pool: agb0
  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 Sat Dec  3 00:06:38 2016
         1 scanned out of 15.3T at 1/s, (scan is slow, no estimated time)
         0 resilvered, 0.00% done
config:

         NAME                                            STATE     READ 
WRITE CKSUM
         agb0                                            ONLINE       0 
    0     0
           raidz3-0                                      ONLINE       0 
    0     0
             diskid/DISK-%20%20%20%20%20WD-WMC4N0H9R07Y  ONLINE       0 
    0     0
             diskid/DISK-%20%20%20%20%20WD-WMC4N0H1PWSJ  ONLINE       0 
    0     0
             diskid/DISK-%20%20%20%20%20WD-WMC4N0K7CPYA  ONLINE       0 
    0     0
             diskid/DISK-%20%20%20%20%20WD-WMC4N0K59SFW  ONLINE       0 
    0     0
             diskid/DISK-%20%20%20%20%20WD-WMC4N0K458X4  ONLINE       0 
    0     0
             diskid/DISK-%20%20%20%20%20WD-WMC4N0K43H7R  ONLINE       0 
    0     0
             diskid/DISK-%20%20%20%20%20WD-WMC4N0K6STAC  ONLINE       0 
    0     0
             diskid/DISK-%20%20%20%20%20WD-WMC4N0K4ZH7A  ONLINE       0 
    0     0
             diskid/DISK-%20%20%20%20%20WD-WMC4N0K6KWMT  ONLINE       0 
    0     0
             diskid/DISK-%20%20%20%20%20WD-WMC4N0K75F6V  ONLINE       0 
    0     0
             diskid/DISK-%20%20%20%20%20WD-WMC4N0K58HHT  ONLINE       0 
    0     0

errors: No known data errors
root at silver:/agp0/admin/scripts #