Xen project Mailing List

2009/3/12 Christopher Smith <csmith@xxxxxxxxxxxxxxxx>

I currently have a few CentOS 5.2 based Xen clusters at different sites. These are built around a group of 3 or more Xen nodes (blades) and some sort of shared storage (FC or iSCSI) carved up by LVM and allocated to the domUs.

I am "managing" the shared storage (from the dom0 perspective) using cman+clvmd, so that changes to the LVs (rename/resize/create/delete/etc) are automatically and immediately visible to all the Xen hosts.

However, this combination seems to be horribly unreliable. Any network hiccup more than a lost ping or two results in cman losing contact with the rest of the machines, which it frequently does not regain. For example, failing one of the bonded NICs usually takes few seconds for everything to 'stabilise' again on the network, but in that time cman has lost contact with all the other nodes and often killed itself (or bits of itself) in the process. Further, I have found I often have to reboot the machine completely to convince everything to start talking nicely again (why this is so, I have no idea, but on more than one occasion I've spent an hour stopping/starting cman and manually killing processes trying to get it working again, with no luck, then had a reboot fix everything instantly).

I am not interested in any fancy failover of domUs, or anything else cluster related on the Xen host side - we address HA and redundancy requirements within the VMs themselves. The only reason I have this stuff setup at all, is to be able to use clvmd. Is there any alternative out there that will let me keep using clvmd (or achieve similar functionality), without having to worry about cman constantly falling over ?

Cheers,
CS
--
Christopher Smith

UNIX Team Leader
Nighthawk Radiology Services
Limmatquai 4, 6th Floor
8001 Zurich, Switzerland
http://www.nighthawkrad.net
Sydney Fax: +61 2 8211 2333
Zurich Fax: +41 43 497 3301
USA Toll free: 866 241 6635

Email: csmith@xxxxxxxxxxxxxxxx
IP Extension: 8163
Sydney Phone: +61 2 8211 2363
Sydney Mobile: +61 4 0739 7563
Zurich Phone: +41 44 267 3363
Zurich Mobile: +41 79 550 2715

All phones forwarded to my current location, however, please consider the local time in Zurich before calling from abroad.

CONFIDENTIALITY NOTICE: This email, including any attachments, contains information from NightHawk Radiology Services, which may be confidential or privileged. The information is intended to be for the use of the individual or entity named above. If you are not the intended recipient, be aware that any disclosure, copying, distribution or use of the contents of this information is prohibited. If you have received this email in error, please notify NightHawk Radiology Services immediately by forwarding message to postmaster@xxxxxxxxxxxxxxxx and destroy all electronic and hard copies of the communication, including attachments.

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users

Re: [Xen-users] Alternatives to cman+clvmd ?