I currently have a server (for a client) in the Dallas data centre. This was originally going to be a development/backup server, with the production server living in Fremont, which has much better latency for Australia.

The plan has now changed. To keep costs down at this stage, there will be no development/backup server, so I have to move what I have to Fremont, with the Dallas one already being in a pre-production stage.

I don't see the move between data centres as taking too long - only 2.7Gb used, including the operating system.

Nevertheless, I need to make sure that the move involves as little downtime as possible.

I have changed the TTL of the DNS records for the domains hosted on that box as low as I can set them (20 minutes.)

Is there anything else I should do or know?

I will need this to happen at a pre-arranged time, so that I can do all the DNS changes and other stuff. Are you Linode guys able to do this? Wouldn't want to submit a ticket and have it happen just some time, as it might be the middle of the night for me and thus put the whole thing out of action for hours on end.

I think migration between datacenters couldn't be more simple and thoughtful. You just have to open a support ticket and the Linode staff will prepare the migration job for you which you will start by hitting the button in your control panel at the time you find it suitable.
So any custom tasks could be done while your image travels.

At least I had it this way when I moved to Atlanta.

@melon - thanks for your reply.

@anyone - is the IP address at the new DC known before the transfer?

I don't know that specific answer. But when you ask for a migration, it doesn't just happen; Linode sets everything up and then you get a big "Migrate" button that you push when you're ready.

Once that button is there, the machine you're moving to has been set, so your IP should be knowable. If it's not on the dashboard, the support folks should be able to tell you. And in any case, you don't actually migrate until you push that button.

Cool, thanks. If I know the IP address when I hit 'migrate', I can make my DNS changes whilst the migration is in progress so downtime would be based on the greater of the DNS TTL or the migration time. (To which I have to add booting the Linode at the end of the progress and seeing what goes wrong.)

Alternatively you could get a second server in Fremont, configure it, copy over your data, check that everything works correctly, change DNS and, once it propagates, close the original server.

More work for you but zero downtime. You'd pay for two servers only for a day or two.

@sleddog - I did consider that. If this had been a server in full production that had to be moved, this is what I would have gone for. (Although if I had to move a server already in full production, it would mean that I hadn't done my planning properly!)

However, I have to keep costs for my client minimised; whilst a day's worth of Linode is neither here nor there (wouldn't even buy a beer!) my time setting up the second server is another matter.

But thanks for the suggestion; it's something to which I had given consideration and, in other circumstances, might have gone with.

You don't have to set up a second Linode, just clone the one you already have (in the 'Settings and Utilities' menu).

_________________
/ Peter

Quick heads-up about one minor issue I had when moving my linode from Atlanta to Newark, so other folks don't repeat my mistake:

After the move I noticed that some processes were inexplicably taking longer. The cause were wrong nameservers in /resolv.conf: the first two resolvers were still the old Atlanta resolvers, which apparently are configured to refuse queries from linodes in other data centres. This caused a small delay for every DNS resolution request until the 3rd fallback nameserver was used.

Putting in the correct resolver IPs fixed things.

If you have configured your linode to get all this info via DHCP you will not have this problem. In my case I had configured all network config statically. I did think of changing the IP addresses of my network interfaces for the move, but I forgot about DNS.

Good point!

@feanor - ooh, good point! I had on my list to configure the interface, but not resolv.conf. Have a beer on me.