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We've got a server running cPanel on CentOS 5.10 currently, and I'm considering whether it's worthwhile or even wise to look at upgrading to CentOS 6.4.

The server is virtualised on 2012 R2 Hyper-V, and I get the impression that CentOS 6.x has better Hyper-V support which would obviously be desirable, but that impression may be flawed.

Looking online I can't find much in the way of documentation on this subject, but some of what I can find indicates that it can be risking, and some people strongly suggest attempting a major version in-place upgrade on a production system is a very bad idea (a view I'm tempted to believe).

Fortunately in terms of testing I do have another box available. We currently have a 2nd licenced cPanel box, running the same OS version (built with the old version purely to test a recent migration from VMWare, so not currently in production), so I can use that to test things initially.

What would people say are the main dangers / pitfalls / likely problems of doing such an upgrade? Is there any real benefit to performing the upgrade (I understand 5.x will continue to be supported for a few years yet)?

Keith Langmead
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1 Answers1

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The main danger is that you end up with an unusable box. In fact 5.10 is still being supported so there's no need to hurry. Nevertheless we migrated several boxes from 5.x to 6.5 and noticed a slight performance increase. Besides this the new release gives you more recent kernel and package options. If that's important for you I'd consider upgrading.

Major version upgrades are a risky thing and even when you carefully check dependency issues and avoid 3rd party repos there is no guarantee that the upgrade will pass without serious issues.

While we did such in place upgrades (always take an image before doing this!) our preferred procedure now is a cPanel reinstall on a fresh RHEL/CentOS installation and then transfer the accounts using WHM's really reliable transfer accounts feature.

Start with one account for testing and if everything works well migrate the rest. Overall downtime for an account is minimized this way!

Some suggestions:

  • lower the DNS record TLL a reasonable time before you start the migration (or reroute IPs once you're done)
  • copy/set relevant settings to the target machine
  • you can also import the most important cPanel settings using a cli tool (doing the whole thing by hand takes around 20 minutes and you're sure everything is set correctly)
  • check if you have conflicting settings/customizations on the machines (e.g. my.ini customizations on the source that prevent some databases to be restored on the target machine)
  • when using roundcube with SQLite on the source server you'll have to switch the new server to SQLite before migrating the first account (otherwise you'll have to migrate afte rmigration -> more hassle)
  • migrate accounts and plans
justlovingIT
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