Migrating to new server with zero downtime

prophecy

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I am in the process of upgrading a server and therefore have to migrate to a new one with new IPs. Now what would be the best way to ensure that the switch is as smooth as possible. You can assume the the second server will be setup the same and working fine, so the big issue is making the dns changes happen without anybody noticing.
 

ProWebUK

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> server 1
> server 2

have them both running sites correctly (if DNS was running towards server 1 everything would be as it is currently, if the dns was pointing to server 2 everything would also be running the same.

Once you have all sites setup correct on server 2 and are working the same as server 1 just switch your DNS over from server 1 to server 2.

You should be able to simply chnage the records for your nameservers and move your main domain across :)

Chris
 

prophecy

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Ya, but there will still be a lot of downtime while the dns changes propogate and all that. How to minimize the dns change downtime is really what i'm looking for. Like some way to point to the new server before it it is up somehow so that when people find the first server down, they will check the second one until the new ip propogates around.
 

ProWebUK

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You don't chnage the nameservers on the domains, you chnage the IPs on the records used for the nameservers

Chris
 

prophecy

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I don't need to change the nameservers, dns is on a different server.
 

ProWebUK

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ProWebUK said:
You don't chnage the nameservers on the domains
Go to your DNS server and update the records for the nameservers themselves, it shouldnt be far from instant.
 

jdwright

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Oct 19, 2003
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Change the SOA TTL for your DNS entries to something like 10 minutes (600 seconds) and let that propogate for the amount of time your last TTL was set to. Then you can change your dns entries and it should only take about 10 minutes to propogate.

You might want to change the SOA Refresh (how long your secondary servers wait before updating) if you run slave nameservers.

Don't forget to change your serial number whenever you make changes! :)


www.dnsreport.com will give you your current settings, then you can edit /var/named/domain.com.db to change the values.
 
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