Server Migration to another ip address

[jokingelephant]

Hi,

I have one server installed with plesk hosted on this ip eg 203.117.83.23. I will need to migrate this server to another ip at 203.118.25.87.

The A/MX/DNS records will need around 24hours to propagate. During the propagation period, i will need to direct all http/mail request from the old ip to the new ip.

I thinking of setting up a new server using this 203.117.83.23 ip address and direct all the mail/http traffic to the current server hosted at the new ip, 203.118.25.87. But how can this been done?

May i know has what will be the best way to move the server to this new ip address with little downtime in http and mails?

Thanks

 

[jokingelephant]

anyone ????

 

[shoggy24]

I just migrated my server, if you are building a new server contact sales and they will send you a temporary license with no restriction to install, it is valid for 14 days. Then use migration manager in plesk to transfer websites and emails plus their configuration, really easy to use.
Update your nameservers and MX and you are done.

 

[breun]

Lowering the TTL for the DNS records involved in this migration in advance (and waiting for this change to propagate) will help a smooth migration. After the migration you can set the TTL to a higher value again. You should also be able to set up iptables on the old host to redirect incoming traffic to the new one.

 

[jokingelephant]

Thanks breun and shoggy24 for your valuable inputs.

Yes, i will use the plesk migration manager to copy the sites over to the new server with the temp license from parallels.

Where/How can i lower the TTL for the DNS records? And how does lowering ttl help a smooth migration?

And how can i set up iptables on the old host to redirect incoming traffic to the new one? I need to forward http requests and incoming mails to the new server while the A/MX/NS/CNAME are propagating which will take a few hours.

Thanks in advance for the inputs.

p/s: newbie in this server migration, hope to minimise the downtime. =p

 

[shoggy24]

basically TTL tells other DNS servers when to update your DNS records they store, that way propagation is a lot faster, to change the TTL, log in to the control panel go to the domain for your nameservers - click on DNS -Click on SOA records - reduce the TTL. I set mine for 1hr because some servers may ignore if set for lower.

 

[breun]

Where/How can i lower the TTL for the DNS records?

At the nameserver that serves the records for the domains that will be migrated.

And how does lowering ttl help a smooth migration?

And how can i set up iptables on the old host to redirect incoming traffic to the new one? I need to forward http requests and incoming mails to the new server while the A/MX/NS/CNAME are propagating which will take a few hours.

It will only take a few hours if your TTL is set to a hew hours. If you lower the TTL it will take a few hours for that change to propagate, but any changes after that (like other IP addresses) will propagate within the new TTL. After the migration you can reset the TTL to a longer value.

I don't have the iptables rules handy, but see the DNAT target for iptables.

 

[jokingelephant]

Oh i see. =)

For example, i have this domain jlcap.com pointing to

jlcap.com 1 NS ns37.worldnic.com 7200s
jlcap.com 1 NS ns38.worldnic.com 7200s

Does that mean i need to go to this ns37.worldnic.com/ns38.worldnic.com plesk cp, under SOA setting(under DNS settings) to change the TTL to 1hour? So after i change the TTL to 1hour, any changes to the ip address to A/MX record will just take around 1hour to refresh globally?

 

[breun]

That change to 1 hour will take 7200s to propagate. After that changes will propagate within that hour. Yes, that's the idea.

 

[jokingelephant]

Btw, has anyone played with qmail forward before?

I will need to forward the incoming emails during the one hour propagation from the old server to the new server.

Thanks
Louis

 

[breun]

You should be able to do that using iptables as well. Easiest solution: just disable SMTP on the old server when switching the DNS records. Others will either already have the new address or try again later and then have the new address.

 

[jokingelephant]

hMM what can i do on the old server's iptables? direct incoming http request and incoming emails?

I cannot afford to switched off the smtp on the old server, which means all the users cannot send/receive emails during the propagation.

thanks

 

[breun]

You cannot have 100% continuous service when migrating a server to a new machine. It will always take time to move the data to the new server and let Plesk configure everything, so even if you redirect traffic to the new server there will be a period of time where things won't work as normal until the migration is finished.