zfs mirror and unequal writes

[Adam Vande More]

On Fri, Dec 8, 2017 at 3:57 PM, Mike Tancsa <mike at sentex.net> wrote:

> I was reading up on SSD life spans and decided to take a quick look at
> how many TBW my disks have gone through. Looking at one box I was really
> surprised at the uneven amount of data written
>
>
> 0{backup4}# smartctl -a /dev/ada0 | grep LBAs
> 241 Total_LBAs_Written      0x0032   099   099   000    Old_age   Always
>       -       21004341355
> 0{backup4}# smartctl -a /dev/ada1 | grep LBAs
> 241 Total_LBAs_Written      0x0032   099   099   000    Old_age   Always
>       -       413475182465
> 0{backup4}#
>
> I was quite surprised that there were WAY more writes to one disk that
> the other.  Give these are zfs mirrors, one says 192TB writes and the
> other is 10TB ?!?!?!
>
> They were installed at the same time
>

Do you have the disks allocated in any other way eg swap or have a member
drop out for awhile?

I checked my mirror which has been in place for ~4 years and the values are
pretty close, although I have different drives which are mechanical.

-- 
Adam