Atomicorp

Interesting project from Google: Page Speed

Currently they have a Firefox/Firebug extension with optimization suggestions and an Apache module for Apache 2.2 packaged for Debian and CentOS. The Apache module can be configured for specific domains and you can configure filters that apply specific optimizations. This doesn't sound like something you'll want to enable by default for every domain on a Plesk server, but it is interesting technology for tuning specific sites.

Some basic stuff lvalics just relayed to me about it:
* cannot be setup per vhost
* on a Joomla sample it introduced JS errors

(Disclaimer: I haven't actually tried the Apache module yet.)

* cannot be setup per vhost

That's too bad. I think I misread the Configuring Domains section as being able to configure for which domains mod_pagespeed will work, but it seems that's only for *additional* resource domains for which mod_pagespeed will do its rewriting.

* on a Joomla sample it introduced JS errors

The various filters have different degrees of risk, but you can enable/disable them individually I believe.

But yes, the Apache module is definitely not something I would throw at every server I come across. Also, I think it's better optimize the application itself before it needs to go through Apache, so the Firefox extension might be interesting there for developers. The Apache module sounds interesting for specific application optimizations.

I have read in another forum that it is possible to run vhost based.
The global httpd.conf should contain at least these entries:
- ModPagespeedUrlPrefix
- ModPagespeedFileCachePath
- ModPagespeedGeneratedFilePrefix

ModPagespeed on/off than can be set via vhost file.
I haven't tested it and I don't know if it's possible to set filters or change coreset-filters via vhost file.

There are several issues that might make mod_pagespeed a bit of a problem. One of the biggest is that it is going to kill some servers (especially busy ones or ones with limited resources) on startup as it learns about the sites and caches stuff.

I think it is way to early to be playing with it at this stage. I'm going to let it mature a bit before even thinking about it.