This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


[Xen-users] Problem in linux domU re: /dev/rtc and hwclock

To: xen user <xen-users@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-users] Problem in linux domU re: /dev/rtc and hwclock
From: Digimer <linux@xxxxxxxxxxx>
Date: Tue, 12 Jul 2011 18:15:37 -0400
Delivery-date: Tue, 12 Jul 2011 15:28:48 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv: Gecko/20110428 Fedora/3.1.10-1.fc15 Thunderbird/3.1.10
Hi all,

  One of our domU VMs (CentOS 5.6 x86_64) runs a cobol application,
which in turn called 'clock' to get timestamps. Changing this is

  When I try to call 'clock --debug' I get:

[root@vm0010 ~]# clock --debug
hwclock from util-linux-2.13-pre7
hwclock: Open of /dev/rtc failed, errno=19: No such device.
No usable clock interface found.
Cannot access the Hardware Clock via any known method.

  The device exists:

[root@vm0010 ~]# ls -lah /dev/rtc
crw------- 1 root root 10, 135 Jul 12 18:00 /dev/rtc

  As I understand it, this is (in part?) to prevent domU from altering
dom0's date/time. Obviously, this is a good thing, but can the device be
made available to domU VMs in a "read-only" mode?


E-Mail:              digimer@xxxxxxxxxxx
Freenode handle:     digimer
Papers and Projects: http://alteeve.com
Node Assassin:       http://nodeassassin.org
"I feel confined, only free to expand myself within boundaries."

Xen-users mailing list

<Prev in Thread] Current Thread [Next in Thread>