From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Mueller Subject: Re: "clocks not synchronized" warning message Date: Thu, 8 Jul 2010 15:44:07 +0000 (UTC) Message-ID: References: <1278598768.2253.18.camel@wido-laptop.pcextreme.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Return-path: Received: from lo.gmane.org ([80.91.229.12]:53202 "EHLO lo.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756545Ab0GHPoZ (ORCPT ); Thu, 8 Jul 2010 11:44:25 -0400 Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1OWtGw-00072Q-5F for ceph-devel@vger.kernel.org; Thu, 08 Jul 2010 17:44:22 +0200 Received: from cust.dyn.95-152-98-129.swisscomdata.ch ([95.152.98.129]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 08 Jul 2010 17:44:22 +0200 Received: from thomas by cust.dyn.95-152-98-129.swisscomdata.ch with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 08 Jul 2010 17:44:22 +0200 Sender: ceph-devel-owner@vger.kernel.org List-ID: To: ceph-devel@vger.kernel.org >> >> How about .5 seconds? We sync our machines to a local ntp server, so >> the clocks get really close (sub-ms). I forget that NTP isn't so >> accurate over a WAN. >> >> The issue is that the monitor leases and timeouts are something like 2 >> seconds (so that failures/unavailability) are detected quickly, so the >> tolerable clock drift can't get too close to that. >> >> sage > > ok, if this is the problem, then I would also recommend running an ntp > daemon (not ntpdate) on every node. A running ntpd will manage the > timesource to be in sync. > > If anyone likes to run an mds/mon on a VM I expect problems - > virtualized clocksources are far less stable (my experience). > started the ntpd on the nodes. now i'm able to run it with "mon lease wiggle room = 0.1". as Wido is using ntpdate and he's successfull with 0.5 I would say 0.5 is possible a good default. - Thomas