From owner-freebsd-stable@freebsd.org Wed Dec 9 17:11:47 2015 Return-Path: Delivered-To: freebsd-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id BCC079D686E for ; Wed, 9 Dec 2015 17:11:47 +0000 (UTC) (envelope-from dustinwenz@ebureau.com) Received: from internet06.ebureau.com (internet06.ebureau.com [65.127.24.25]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "internet06.ebureau.com", Issuer "internet06.ebureau.com" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 9DF3F1D1A for ; Wed, 9 Dec 2015 17:11:47 +0000 (UTC) (envelope-from dustinwenz@ebureau.com) Received: from localhost (localhost [127.0.0.1]) by internet06.ebureau.com (Postfix) with ESMTP id 392084B1D4CB; Wed, 9 Dec 2015 11:11:45 -0600 (CST) X-Virus-Scanned: amavisd-new at ebureau.com Received: from internet06.ebureau.com ([127.0.0.1]) by localhost (internet06.ebureau.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id HAvxcIUH0ZVl; Wed, 9 Dec 2015 11:11:44 -0600 (CST) Received: from square.office.ebureau.com (unknown [10.10.20.22]) by internet06.ebureau.com (Postfix) with ESMTPSA id A1E424B1D4BB; Wed, 9 Dec 2015 11:11:44 -0600 (CST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 9.1 \(3096.5\)) Subject: Re: Periodic jobs triggering panics in 10.1 and 10.2 From: Dustin Wenz In-Reply-To: <56680148.9070601@rlwinm.de> Date: Wed, 9 Dec 2015 11:11:44 -0600 Cc: freebsd-stable@freebsd.org Content-Transfer-Encoding: quoted-printable Message-Id: <19A6FFCC-6B3A-44EB-B96F-D02F98364C3F@ebureau.com> References: <34FA7D40-8758-460D-AC14-20B21D2E3F8D@ebureau.com> <1449619470.31831.9.camel@michaeleichorn.com> <56680148.9070601@rlwinm.de> To: Jan Bramkamp X-Mailer: Apple Mail (2.3096.5) X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Dec 2015 17:11:47 -0000 PF filed: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D205163 Please let me know if there is any more useful information I can = include. - .Dustin Wenz > On Dec 9, 2015, at 4:24 AM, Jan Bramkamp wrote: >=20 >=20 >=20 > On 09/12/15 01:04, 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. >>>=20 >>> I've been able to alleviate this problem by disabling the security >>> scans within the jails, but leave it enabled on the root host. >>=20 >> 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'. >=20 > While jitter would reduce the resource contention a thundering herd of = cronjobs shouldn't cause the kernel to divide by zero. Spreading the = load by introducing jitter to cronjobs might hide the problem, but it = still needs further analysis. >=20 > @Dustin Wenz: Can you reproduce the problem and file a PR to track = this? > _______________________________________________ > freebsd-stable@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to = "freebsd-stable-unsubscribe@freebsd.org"