zpool CKSUM 0 --> 1 while resilvering

[Janos Dohanics]

On Mon, 15 Feb 2021 12:56:31 -0800
David Christensen <dpchrist at holgerdanske.com> wrote:

> On 2021-02-15 10:11, Janos Dohanics wrote:
> > [...]
> > 
> > # zpool status
> >    pool: zroot
> >   state: ONLINE
> > status: One or more devices has experienced an unrecoverable
> > error.  An attempt was made to correct the error.  Applications are
> > unaffected. action: Determine if the device needs to be replaced,
> > and clear the errors using 'zpool clear' or replace the device with
> > 'zpool replace'. see: http://illumos.org/msg/ZFS-8000-9P
> >    scan: resilvered 1.97T in 0 days 08:25:27 with 0 errors on Mon
> > Feb 15 05:09:47 2021 config:
> > 
> > 	NAME        STATE     READ WRITE CKSUM
> > 	zroot       ONLINE       0     0     0
> > 	  mirror-0  ONLINE       0     0     0
> > 	    ada0p3  ONLINE       0     0     0
> > 	    ada3p3  ONLINE       0     0     1
> > 	    ada2p3  ONLINE       0     0     0
> > 
> > errors: No known data errors
> > 
> > No errors reported by smartctl(8) for /dev/ada3.
> > 
> > Can I consider this a harmless error and should I just run "zpool
> > clear ada3p3'?
> > 
> > Please advise.
> 
> 
> STFW 'zpool status cksum':
> 
> https://docs.oracle.com/cd/E19120-01/open.solaris/817-2271/gbcve/index.html
> 
> https://docs.oracle.com/cd/E19120-01/open.solaris/817-2271/gbbzs/index.html
> 
> I would:
> 
> 1.  Check for interface, cable, and/or rack errors.  These should 
> generate error messages in dmesg(8) and /var/log/messages.  I
> especially hate red, non-locking SATA cables without any speed
> marking.  More than a few people agree that the red dye in the
> insulation will corrode copper.  I have replaced all of my  SATA
> cables with new black, locking, 6 Gbps SATA cables (made by Cable
> Matters).

Red SATA cables? I was certainly ignorant about this!

> 2.  If and when all of the above is okay, I would run SMART short and 
> long tests on all three drives.  (I used to believe in manufacturer 
> diagnostic tools, but recent experiences with Seagate and Western 
> Digital have convinced me otherwise; notably when following up with 
> technical support.  If anyone knows of a brand of HDD with good
> drives, good diagnostic tools, and good technical support, please
> advise.)
> 
> 3.  If and when all of the above is okay, I would scrub the pool.
> 
> 4.  If and when all of the above is okay and CKSUM remains (#3 might 
> clear it?), I would do the 'zpool clear ...'.

Thank you for the comprehensive advice, I'm glad I asked...

-- 
Janos Dohanics