Ferenc Wagner wrote:
Christopher Smith <csmith@xxxxxxxxxxxxxxxx> writes:
I am "managing" the shared storage [...] using cman+clvmd [...]
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.
This isn't inherent to cman, I've been using it for years without much
problem. You have to handle fencing correctly, otherwise it will bite
you, no matter what timeouts you configure. But otherwise, it's OK.
Well, I use manual fencing...
I realise this is less than ideal, but it's far more ideal to me than a
xen host getting fenced and taking out twenty VMs. Especially given how
frequently it seems to get to the point where it would have fenced
something.
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.
This shouldn't happen. Either you misconfigured your bonding (though
a few seconds failover time doesn't sound gross), or more likely you
misconfigured cman: it's defaults aren't this strict, even.
This was actually a problem on the switches, something to do with STP -
the bonding failovers were actually taking a bit over 30 seconds, so
that's probably why cman was falling over.
Having said all this, managing the cluster infrastructure for so
little (clvm only) feels excessive indeed. But I don't know any
better way (other than doing volume management on the storage side).
And volume management on the storage side brings along its own set of
complications. :(
--
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
|
Home