SMART: disk problems on RAIDZ1 pool: (ada6:ahcich6:0:0:0): CAM status: ATA Status Error

Freddie Cash fjwcash at
Tue Dec 12 18:43:51 UTC 2017

On Tue, Dec 12, 2017 at 10:21 AM, O. Hartmann <ohartmann at>

> Question: is it possible to simply pull the faulty disk (implies I know
> exactly which one
> to pull!) and then prepare and add the replacement HDD and let the system
> do its job
> resilvering the pool?

​zpool offline <poolname> <device name>

Do that first.  That will mark the drive as offline, put the pool into a
degraded mode, and generally be less harmful to the system.

Then figure out which disk to pull and remove it (doing it from a powered
off state if needed).

Install the new drive, configure it however it's needed, then use:

zpool replace <poolname> <old device> <new device>

> Next question is: I'm about to replace the 3 TB HDD with a more recent and
> modern 4 TB
> HDD (WD RED 4TB). I'm aware of the fact that I can only use 3 TB as the
> other disks are 3
> TB, but I'd like to know whether FreeBSD's ZFS is capable of handling it?

​Yes, it can handle it just fine.  And it will keep the extra space as
"usable in the future", so if you replace all the drives with 4 TB ones,
the extra space will be added to the pool.

Freddie Cash
fjwcash at

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