Multiple WordPress, eAccelerator, W3 total cache on VPS

At the moment I’m using WP-Minify and Hypercache on all blogs (and yes, for good or ill I am using YARPP); I’m considering switching to W3 total cache and installing eAccelerator. I realize that memcached would be unsuitable for a VPS on Pair.com as there’s only 500MB of RAM.

It’s not that memcached is unsuitable, it’s more so that it’s unnecessary. The performance difference between APC and eAccelerator is going to vary server to server and theme to theme, so unless you really want to take the time to discover, I’d recommend using APC and W3 Total Cache as your caching pair for database and minify and then using disk enhanced mode as page caching method for all of your blogs. This will scale your VPS tremendously.

Obviously you’ll want to disable unnecessary modules on your Apache configuration and any unnecessary processes to get the most out of your server.

As I previously had a limited number of databases, I have several blogs using each database with different table sets. As the database limitation no longer applies, I presume it would be preferable for me to change to using one database per blog? Anyone know the simplest way of doing this?

Using one database for all blogs should be fine. If you experience locking issues, switch to InnoDB to mitigate that. You can always switch to separate databases later if you want.

Hi Frederick,

I have now switched over to W3 TC for most of my blogs. You have provided a lot of information on settings in your answers to people on forums (you’re very active!) and this has been a big help to me in configuring my set-up. I had a couple of glitches where there was a large spike in load due to the swap file getting filled up, but it appears that this was not due to W3 TC but coincidental. At any rate, nobody at Pair (where I am hosted) could tie down an explanation.

I have not yet implemented APC but have already noticed substantial improvements. As soon as I have completed upgrading my blogs to 2.91 etc I will be trying out the op-code cache. I’m a little concerned about dedicating 128 MB to it as I only have 512 at the moment, and I am informed by Pair that Apache takes about 200 MB. Have you any suggestions as to modules that should be on my list for deactivating? I am not a programmer, so it may be that I could lose some of the more developer orientated modules. Any suggestions welcome.

I also haven’t set up the (in my case) on disk CDN yet, but as my theme is a little image heavy this may be a good idea.

Thank you for your stalwart work in putting this plug-in together, and supporting it so well.:-))

Tony Page

I had a couple of glitches where there was a large spike in load due to the swap file getting filled up, but it appears that this was not due to W3 TC but coincidental.

You have to be careful with your configuration settings. If you have a standalone server and a number of other specific variable settings you can actually overwork your server, it’s not that you run out of memory it’s that it’s misused.

So again if you use APC rather than memcache + memcached, you will realize better results on a standalone server.

I’m a little concerned about dedicating 128 MB to it as I only have 512 at the moment, and I am informed by Pair that Apache takes about 200 MB.

I’ll reserve my comments about pair hosting. Let’s just say I’m not interested in the opinions of hosting providers. Anyway, the amount of memory dedicated is dictated by allowing your site to run for 6-24h and seeing what kind of memory is consumed with your settings. Then you can back down the memory limit.

Regardless, opcode caching is built into PHP6 (APC), so the issue of need for it etc is completely moot.

I also haven’t set up the (in my case) on disk CDN yet, but as my theme is a little image heavy this may be a good idea.

All sites need a CDN. Contact me for recommendations.

Fredrick, I installed Total Cache myself and I have been having problems using eAccellerator. I installed eAccellerator and I see it properly configured under phpinfo() but it is still grayed out under Total Cache.

I see you don’t recommend using eAccellerator for page cache, I thought it sounded funny to have an option to php compile cache pages but enhanced disk is best for page cache unless you go memcached right?

Why is APC a better choice than eAccellerator? I thought eAccellerator was a more popular choice, so I went that route. If you instal eAccellerator/APC, does everything just all of a sudden take advantage of it (wordpress, and all other php apps) or do they have to actually specifically support it (i.e. Total Cache selecting which caching method).

Also, I’d love to hear your feedback on CDN. You mention all sites should use CDN. Why is this and is the one you recommend Amazon S3 I assume?

I originally was using Super Cache but came across your plug-in from Rocking WordPress blog and the plug-in is very impressive.

I tried using APC and got blank pages, after a quick google search I found out there is a compatibility issue with Zend 3.x, we have an app that requires Zend 3 so we cannot remove this, but I did temporarily and not only did the blank pages stop I was able to select APC as an option from Total Cache without any issues.

It looks like there is no way to get APC (perhaps when PHP6 is released but not as it is) to work while supporting Zend 3 on the same server. So this leaves xCache/eAccellerator as the best remaining options.

I was curious, would using OPCACHE provide any advantages for pages or is disk enhanced the best option unless you support memcached?

I see you don’t recommend using eAccellerator for page cache, I thought it sounded funny to have an option to php compile cache pages but enhanced disk is best for page cache unless you go memcached right?

Use which ever opcode cache you like. The explanation as to which cache method is best for which use case is actually quite a bit to explain. The suggestions in the plugin are usually ideal.

Why is APC a better choice than eAccellerator? I thought eAccellerator was a more popular choice, so I went that route. If you instal eAccellerator/APC, does everything just all of a sudden take advantage of it (wordpress, and all other php apps) or do they have to actually specifically support it (i.e. Total Cache selecting which caching method).

Better is a relative thing. An opcode cache improves the performance of all PHP applications automatically. If using eAccelerator 0.9.3 or earlier you can use it for caching with W3TC.

I’d love to hear your feedback on CDN. You mention all sites should use CDN. Why is this and is the one you recommend Amazon S3 I assume?

No. You can contact me directly for specific recommendations.