Server to server Incremental Migration -- steps for hostname & IP configuration

[chiterri]

Hello,

We have been using some Community scripts to manage Zimbra Backup & Restore. With over a thousand users, I want a much better solution. After conversations with others I've downloaded ZExtras for a trial, and if it works like I believe it will, it will be my choice going forward.

We are upgrading the Zimbra7 production server to new hardware; At the same time we will upgrade to Zimbra8. When its done I will turn off the Z7 server using only the Z8 server in the future.

As I understand, I can use ZExtras Backup to execute a migration between a Z7 & Z8 server with very little downtime, using an Incremental Migration process.

I've read Forums posts and the online documentation. I understand the general process for migrations, but everything I read still misses clear details for configuring the Destination server.

I see many people have some similar questions. I hope to get a "once & for all" answer that is useful for everybody!


My current situation is:

Z7 runs on Ubuntu10.
ZExtras Suite Core & Zimlet are installed
there is NO nameserver running on the Z7 server; there IS a nameserver on the same LAN.
the Z7 server's hostname ~= "zimbra.domain.com".
the Z7 server's IP = 192.168.1.42
the Z7 server's main domain is "zimbra.domain.com"
the Z7 server's SSL cert is for "zimbra.domain.com"

Forward & Reverse DNS is configured so

dig A zimbra.domain.com +short
192.168.1.42
host 192.168.1.42
42.1.168.192.in-addr.arpa domain name pointer zimbra.domain.com.

And the /etc/hosts on it is

127.0.0.1 localhost.localdomain localhost
192.168.1.42 zimbra.domain.com zimbra
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

It works this way very well and with no problems.

I will set up the new Z8 server on Ubuntu 12 on a machine that is on the same LAN.

The IP address & hostname of the Z8 server must in the end be the same as the Z7 original server.

But we cannot have these the same during the Z8 installation and the Z7->Z8 Incremental migration.

My detail questions are, to make the Zextras Incremental Migration work without problem,

(1) When I 1st setup the machine for the Z8 server, what must be

its FQDN hostname?
its IP address?
the DNS results for its hostname & IP?
the contents of its /etc/hosts?

(2) When I install Z8 on the Z8 server machine, what must be

the main domain I assign to Z8?

In the end I am looking for the Step By Step sort of Guide for this specific procedure!

<Chiterri>

[Cine]

Hello Chiterri,
welcome to the forums!

One answer for both (1) and (2): for what concerns the migration process through ZeXtras Suite, anything you want!
ZeXtras Suite is not affected by the change of any of the settings you listed.

The only issue I see here is the IP concurrency risk you are taking by not changing the IP address of the server (which would be the easiest solution, as you can install and configure Zimbra on a new LAN IP and then reconfigure your Firewall and DNS according to the change).

If you are running on a Virtual Environment, I suggest you to check out a similar discussion which has been started a few days ago, while if you are running on a physical environment your only option is to set up the destination server with a different LAN IP, then when the moment of the "switch" comes you'll need to reconfigure the Z7 server to use the "spare" IP and the Z8 server to use the "production" IP reconfiguring the /etc/hosts files accordingly - mind that this will surely cause some downtime and DNS caching issues for your users.
In order to minimize the cachin issues, I suggest you to set up an internal DNS service (like described in the Zimbra Installation Guide) as Zimbra's LDAP is very picky about IP changes since it resolves the server's hostname in order to bind to the server's IP address.

Feel free to ask any additional informations you might need...

Have a nice day,
Cine
the ZeXtras Team