Re: Speaking about pure fail over - what about pen itself ?

Ulric Eriksson wrote:
>
> On Mon, 27 Mar 2006 fernando_at_fernandoibanez.com wrote:
>
>>> I'm only looking at two boxes, except that they will also balance other
>>> services located elsewhere. Should the separate interfaces that pen
>>> listens to (not the shared one), be real or can they be virtual ?
>>> Also, if going with independent LB boxes (such as the original example),
>>> do they need to be powerful boxes ? TIA...
>>
>> A simple and cheap way to do failover for pen would be using
>> failover at the DNS level - with a service like
>> Zone Edit (http://zoneedit.com/)
>>
>> ZoneEdit can test if the server is up and if it is not, it can point
>> your domain to a different IP possibly on a different network.
>
> I'm positive that can't work. The old address will be cached on several
> levels throughout the Internet and there is no way to clear all those
> caches from a central point. If they charge money for the service, it's
> a hoax. Otherwise it's just silly.
>
> Multicast in Linux isn't very reliable (or I'm simply incompetent), så
> the vrrp solution isn't as good as it seems. The easiest solution is to
> point the domain to two addresses, one for each pen instance.
>
> Actually, the easiest solution is to install pen on a single server and
> forget about it, at least as long as the hardware is reliable.
>
> Ulric

You could also use CARP, free and cross platform. Available on OpenBSD,
FreeBSD, NetBSD, Linux (http://www.ucarp.org/project/ucarp). Probably
will also make it into MacOS X at some point.

Cheers,
Dom
Received on Mon Mar 27 2006 - 20:40:58 CEST