I am using Google's mod_page speed with Apache on Centos 5.X VPS (I'm not 100% sure on the exact Centos version, but I know it's in the 5 series.)

I am hosting numerous WordPress websites with W3 Total Cache, all of which have the latest version of WordPress and W3TC installed.

Now, here's my issue. When editing any sort of "front-end" code (HTML, CSS, JS, ETC), it does not update after the page has been rendered for about 5 minutes.

I have cleared ALL W3TC caches and cleared browser caches. Normally in the past (before installing of Google's mod_pagespeed) this would have cleared and updated instantly. Ever since installing mod_pagespeed, I have ~5min delay (sometimes longer) of all front-end code updating (even after clearing caches).

I have heard running mod_pagespeed on a VPS is a big NO-NO. Any feedback on this rumor?

I have also heard running mod_pagespeed in combination with W3TC (W3 Total Cache -- WordPress plugin) is another big NO-NO. Any feedback on this?

What is causing this issue?

  • Is it normal? Should I just ignore it & work around it?
  • Is it because mod_pagespeed is still buggy?
  • Is it because I shouldn't be running mod_pagespeed on a VPS?
  • Is it because I shouldn't have BOTH mod_pagespeed & W3TC installed? (Are the conflicting?)

Or are all of the above irrelevant? Should I just make all of my changes on a local development server, then upload to the live server once final changes have been made?

mod_pagespeed appears to run perfectly other than that annoying 5 minute delay on front-end code changes.

So many questions, with so little knowledge. If you know anything about this delay with mod_pagespeed, please enlighten me with your thoughts on this particular situation.


Looks like you need to clear mod_pagespeed cache. Please see mod_pagespeed FAQ: How do I clear the cache on my server?

We have also heard of issues related to running both mod_pagespeed and other caching systems (especially W3TC), but it doesn't sound like that is your problem.

mod_pagespeed should work fine on a VPS.


mod_pagespeed does not care if you're on a VPS. Nor does the VPS care.

Comparing HTTP headers between mod_pagespeed enabled and disabled should give you some clues, but to make it short: part of what mod_pagespeed does is making sure proper (or in this case, surprising) Expires and Cache-Control headers (and the like) are set. This directly influences caching behaviour for everything along the way from your Apache (w/ mod_pagespeed) to your browser.

The simple answer would thus be: yes, running both mod_pagespeed and something else that does caching (I know nothing about W3TC) could lead to interesting results.

Longer answer (for you): look into what exactly both do and figure out what settings to tune, if there are any.

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