Periodic jobs triggering panics in 10.1 and 10.2

[Michelle Sullivan]

Michael B. Eichorn wrote:
> 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'.
> _______________________________________________
>   

No that will just hide it (if successful at all) and it won't work in
all cases.

... i386 is even worse for similar (not the same) instability triggered
by the same scripts ... because zfs should not be used with the stock
i386 kernel (which means if you're using it the whole patching process
with freebsd-update won't work or will 'undo' your kernel config.)

Personally I think zfs should be optional only for 'advanced' users and
come with a whole host of warnings about what it is not suitable for....
however, it seems to be treated as a magic bullet for data corruption
issues yet all I have seen is an ever growing list of where it causes
problems.. when did UFS become an unreliable FS that is susceptible to
chronic data corruption?

-- 
Michelle Sullivan
http://www.mhix.org/