Periodic jobs triggering panics in 10.1 and 10.2

[Michael B. Eichorn]

On Tue, 2015-12-08 at 16:31 -0600, Dustin Wenz wrote:
> I suspect this is a zfs bug that is triggered by the access patterns
> in the periodic scripts. There is significant load on the system when
> the scheduled processes start, because all jails execute the same
> scripts at the same time.
> 
> I've been able to alleviate this problem by disabling the security
> scans within the jails, but leave it enabled on the root host.

To avoid the problem of jails all starting things at the same time, use
the cron(8) flags -j and -J to set a 'jitter' which will cause cron to
sleep for a random period of specified duration (60 sec max). Cron
flags can be set using the rc.conf variable 'cron_flags'.