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Message-ID: <1449619470.31831.9.camel@michaeleichorn.com>
Subject: Re: Periodic jobs triggering panics in 10.1 and 10.2
From: "Michael B. Eichorn" <ike@michaeleichorn.com>
To: Dustin Wenz <dustinwenz@ebureau.com>, freebsd-stable@freebsd.org
Date: Tue, 08 Dec 2015 19:04:30 -0500
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References: <34FA7D40-8758-460D-AC14-20B21D2E3F8D@ebureau.com>
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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'.