Web Hosting Talk : Web Hosting Main Forums : Web Hosting : Question about moving hosts

[abbas]

Hi.

I am currently moving hosts for a domain I manage for my friend. (Im not in the hosting business, just manage the design of the site).

Anyway, how can I move hosts with zero downtime?

I know I upload site files to new host and then when I change the dns, the site will bounce from the old to new, so thats ok.

BUT, what about email? I mean, we can use pop/imap to download all emails on local machine and then to upload it back on the new host. But what about incoming email? Does that go to the new host or the old? Also, can this all be scripted. So that you manually upload the new site, and then have a script on corn job that checks the old imap server for email... but what about duplicated (if email is sent to both servers)???

I am surprised no one asked this before on WHT???

Thank you for your help.
Abbas.

[darko886]

I doubt it, there might be a way but it usually takes a while for the dns servers to update, for example when I moved hosts it took me about 12 hours.

[DimensionServers]

Email might be a little more tricky. you should however be able to forward the emails to the new server when it is live.

[AMJones]

Before you move, ping the mail server, and get the IP.

Once you change DNS, the mail server you're checking will - of course - become the new one.

Once this happens, change your e-mail software to check the IP of the old mail server... you'll get any e-mail that might have collected there during the change.

You may have to switch back and forth a few times throughout the course of a few days to make sure you get everything - but lately DNS switches seem to go pretty quickly all things considered.

Hope this helps.

[wsfeb]

It can take from 2 hours to 24 hours depending your domains DNS propagation on web.


Thanks

[abbas]

Hi.

Thanks for the reply...

Ok, email gets sent to whatever server (new or old) depending on how fast dns goes. Ok, does anyone have a script which logs into the old imap server and compares emails to find any new ones and then copies these over? Although, wont this cause all new emails to be marked as "read"???

Thank you very much for your info.

[bear]

I'd suggest changing the DNS zone on the losing machine to show the IP address of the new machine when you're ready. The MX record refers to a canonical name: "domain.com.", which is translated by the A record (name to IP) in the zone. If the A record IP is off server, mail *should* go to the new one right away.
At least I've never seen mail on one of mine be delivered locally once I'd done this. Maybe lucky and no mail came in?

[abbas]

Hi. Thanks for that, will look into it...

Is there no "procedure" for complete mail transfer with no loss of emails and emails moved across new server?

[Asterisk Techs]

1). Anyway, how can I move hosts with zero downtime?

Ans: It is impossible to move hosts with zero down time, but we can make it minimum by following method.

STEPs:

1. Take the latest backup of account from the old server
2. Restore the backup in the new server.
3. Ask the old server to change the dns zone file in such a way that the domain will point the new server.
4. Ask the domainname registrar to update the nameservers

The above steps will minimize down time.

2. How to prevent email missing while account transfer

Option1: There will be a time delay for taking latest backup from old server and restoring it in the new. After this you need to point the old servers zone record to new server. All these work will take less than 30 mins. During this interval all the emails go to old server. So restored account in the new server will not contain these emails. To solve this you can take a copy of inbox from old server and paste it in the new. Following are the steps

1. copy the inbox from old account to new server as inbox.old
2. make sure that the file inbox.old has ownership owner.owner and permissions 600.
3. Edit the file .mailboxlist ( /home/account/mail/domain.com/mail.username/.mailboxlist) and append the line inbox.old.

This will help to restore the missed emails while account transfer.

Option2: Keep downloading mails to local machine with one minute interval.

So mails that comes to old server ( Before pointing it to new : step 3 ) will received on the local machine.


Best regards,
Asterisk Techs
asteriskssoft.com

[abbas]

mmm... i see thanks for that...

What happens to someone who runs a free email service and they want to move hosts?

Thanks for all your info guys.

[Asterisk Techs]

Hi,

If all the email users would configure a mail client to download mails to the local machine ( With time interval for download should be a couple of minutes ) while the transfer is being done. Thus all the mails would be downloaded to your local machine even in the time of transfer.

Hope this helps

Best regards
Asterisks Techs
asteriskssoft.com

[CyberHostPro]

or login to the old hosts webmail client after the transfer is complete, or as per above download to your local machine, if you use outlook for pop3, then set it to check every 1 minute :p

[abbas]

Great, thank you very much for the heads up...

Regards.

Edit :: Spelling.

[Swelly]

Generally speaking you can do a flawless transfer by having the provider move your data to their network, and you add nameservers to your domain registrar. Once the NEW nameservers have propagated to the new host, delete your own ones out of your registrar.

[StackHost]

Originally Posted by HostFrog

Generally speaking you can do a flawless transfer by having the provider move your data to their network, and you add nameservers to your domain registrar. Once the NEW nameservers have propagated to the new host, delete your own ones out of your registrar.

Hostfrog, this would work if the user was not worried about the intermediate time between propagation, during which time some e-mails will be on one server and some on the other, it can get very confusing.

OP, you may want to look at a tool called rsync. You should be able to create a mirror of the old server to the new server, so that all updates as they are made to the old server are automatically made on the new, without having to worry about DNS.

Good luck. Let us know how it goes.