On Jun 19, 2009, at 4:43 PM, [email protected] wrote: > my big problem with live migration (especially as a disaster > recovery 'solution') is that if the running machine dies it's too > late to do a live migration. If the application is important enough > to need failover and disaster recovery I need it to be able to > survive a system just disappearing, and so I need it to be able to > recover on the new machine without having the old machine available > to migrate from, and if I have that anyway, why not use that instead > of live migration?
That's also a feature in the new version of ESX, what they call "constant availability", where the state of the VM is maintained on two different ESX hosts simultaneously. If the "live" one fails, the "standby" unit takes over. If the standby unit fails, a different unit in the resource pool takes over as "standby" and assumes the responsibility of being "available". > I can see live migration as being handy for maintinance and planned > changes, but it's not _that_ hard to plan to do the failover at off- > peak times when a few seconds of outage aren't a problem. It's all about "what can your environment handle". For some environments, a couple seconds of outage is fine. For others, that's completely not acceptable. You have to plan your budget dollars in indirect proportion to the amount of downtime you're willing to accept. The less downtime, the more it costs. :-) Cheers, D _______________________________________________ Discuss mailing list [email protected] http://lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
