Enable PHP optimisation for Magento site

[regisit]

We have a dedicated server in default cPanel configuration (running suPHP). There is currently one cPanel account running a Magento store. The server may run additional WordPress sites at a later date, but all are owned by the same company - ie. no shared hosting with anyone else. The server has 32GB RAM.

Magento is a massive beast with thousands of PHP files and the site speed needs improving. All indicators point to PHP optimsation as a good way to achieve this if we have the memory available for the caching - which we do. However, with suPHP there no scope for this. The site is live so no "try this and see if it works" options allowed! We need a 100% certified safe approach. This question is multi-fold:

Should we switch to DSO or FCGI so that we can enable eAccelerate?
I've read that switching to DSO can cause issues due to file permissions. Magento permissions are mostly 755/644 but DSO needs 777 apparently. Is FCGI the better option for a site that currently works fine with suPHP?

Is eAccelerate like to result in a measurable improvement in response times for Magento
Ideally looking here for comments from anyone who has actually done this and seen a marked improvement

Is there a better alternative to eAccelerate supported on WHM/cPanel e.g. APC?
Again, anyone used an alternative configuration on WHM/cPanel and seen marked improvements? If so, what are the steps to switch from suPHP with no optimisation to something else with, in a totally risk free way?

Thanks.

 

[cPanelMichael]

The site is live so no "try this and see if it works" options allowed! We need a 100% certified safe approach.

You may want to consider setting up a development environment to make sure any changes you make do not result in error messages on your website. While switching PHP handlers is straightforward for the most part, it is possible that some scripts may require different permissions on DSO compared to suPHP.

Thank you.

 

[regisit]

Yes, that would be simpler to achieve if cPanel allowed us to set up a test server under the licensing terms. But I understand that cPanel has no such test/backup server licensing allowance.

 

[Infopro]

We need a 100% certified safe approach.

Yes, that would be simpler to achieve if cPanel allowed us to set up a test server under the licensing terms. But I understand that cPanel has no such test/backup server licensing allowance.

Correct. If you need to have a 100% safe approach, you might want to pick up a VPS for 20 bucks somewhere and test there. That's how most Hosting Providers do this sort of thing.