Date: Sun, 2 Jan 2011 10:33:34 GMT From: Greg Holmberg <fbsd-9.0-aws-ec2-1293964000@holmberg.to> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/153620: Xen guest system clock drifts in AWS EC2 (FreeBSD 9.0-CURRENT i386 T1-micro) Message-ID: <201101021033.p02AXYYJ070846@red.freebsd.org> Resent-Message-ID: <201101021040.p02AeDOA030300@freefall.freebsd.org>
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>Number: 153620 >Category: kern >Synopsis: Xen guest system clock drifts in AWS EC2 (FreeBSD 9.0-CURRENT i386 T1-micro) >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Sun Jan 02 10:40:13 UTC 2011 >Closed-Date: >Last-Modified: >Originator: Greg Holmberg >Release: 9.0-CURRENT i386 >Organization: >Environment: FreeBSD domU-12-31-39-13-00-E9 9.0-CURRENT FreeBSD 9.0-CURRENT #88: Wed Dec 29 09:55:39 UTC 2010 root@chch.daemonology.net:/usr/obj/i386.i386/usr/src/sys/XEN i386 >Description: 9.0-CURRENT system running as AMI in Amazon EC2 cloud keeps poor time. System was under heavy load, repeatedly compiling packages to exercise memory allocation code. Clock in guest should be updated faithfully by the host. Clock in this AMI drifted 2200 seconds over 11 hours. >How-To-Repeat: >From Amazon AWS Console, start a FreeBSD instance. I used ami-a0fc0dc9, the most recent 9.0-CURRENT available on Dec 30, 2010. Wait a few hours. (Maybe use it heavily?) Compare the correct time from a good NTP source with the AMI system clock. >Fix: No known fix. (Didn't rtfs yet) Workaround: perhaps run ntpdate out of cron every twenty minutes? >Release-Note: >Audit-Trail: >Unformatted:
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