On Fri August 24 2007 15:12, Brian Mathis wrote:
> On 8/24/07, Chris Boyd <cboyd@xxxxxxxxxxxxxxxxx> wrote:
> > On Aug 23, 2007, at 10:30 PM, Feizhou wrote:
> > > Keep or setup a box inhouse to show the message, when the servers
> > > are online in the data center, switch ips for the names over and
> > > then change the setup on the box to either redirect or proxy the
> > > requests to the real servers to handle incoming http requests due
> > > to cached dns entries.
> >
> > Also, lower the cache time in your nameserver's zone files so that
> > people will see the new IP addresses faster. 3600 seconds works
> > pretty well, but I've used as little as 120 seconds for sites that
> > are more popular.
> >
> > --Chris
I would add that you change the TTL's about a day before the move or at a
minimum the amount of time the TTL is set for. Then when you change DNS for
the move this information will be updated quicker for the client and the
correct record will get out sooner.
Here is another thing you might think about. If the sites content doesn't
change often maybe you could leave the site up until the new hosting site is
setup and then just change DNS to point to the new site. Make sure you
change your DNS TTL's to a low number the day before. Then after the switch
is made update DNS to the new IP Addresses and TTL. Then you just have to
wait till the short TTL's have expired and then you could turn off the server
on your site Since I don't know your setup I cannot tell you what would be
best. Of all the choices this I find to be the best. No down time for the
client.
> Messing with DNS is really the wrong way to go on this. You'd be
> forcing all of the DNS servers involved to start messing with their
> caches, update more frequently, etc.., pushing the problem out onto
> "everyone else", and you have no control over any of it really. Cache
> time is only a suggestion, and not all DNS servers follow it.
DNS is the proper way to go with this. That is the job of DNS. DNS Cache is
being updated all the time including your desktop. While TTL's of 120 are
short it does nothing more then tell the Cache when to expire the record.
This ensure that the most up-to-date record is in it's cache. You would be
surprised to know that there are site with TTL's of 0. This just tells the
cache to drop the record as soon as it gets it.
> The way to go is to assign that same IP address to another box during
> maintenance, and have that box show the page. Then you have full
> control over when the switch happens. The only potential issue there
> is ARP caching on your local network.
Please explain how they will lose any control over when the switch happens?
They are in control of their DNS. They make the changes. They are moving
the boxes off site so they have to update DNS anyway.
--
Regards
Robert
Smile... it increases your face value!
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