Migrate from IISpeed

IISpeed is deprecated; its successor is the native IIS module that mod_pagespeed 2.1 ships, from the same code lineage. The move is an uninstall, an install and a check: your configuration files and your cache directory stay in place and keep working. The IIS package ships from the 1.15 packaging channel.

Before you start

1. Save your configuration. Copy the iiswebspeed.config files (the server-level one under %ProgramData%\We-Amp\IISWebSpeed\ and any per-site file in a site’s physical root) somewhere safe. You will not need to edit them, but you want the copy if you roll back.
2. Keep the IISpeed installer you installed from. It is your rollback.
3. Leave the cache. The module reads the cache directory IISpeed used; there is nothing to drain.

Steps

1. Uninstall IISpeed. Apps & features (or Programs and Features) → remove “IISpeed”, then run iisreset so no worker process still holds the old module. The two modules register the same handler in IIS and cannot coexist; this step is not optional.

2. Install the module. Download the signed MSI from the download page and run it, then iisreset. The installer registers the module as a native HTTP module and creates the default cache directory at %ProgramData%\We-Amp\IISWebSpeed\Cache. Install on IIS has the requirements.

3. Check that the configuration is read. The module looks for pagespeed.config first and iiswebspeed.config second, in the site root and then at the server level, so your files are picked up as they are. The iispeed directive prefix is accepted alongside pagespeed and ModPagespeed. A cache path inherited from IISpeed under the IISWebSpeed tree keeps working, and each site’s cache subdirectory is created on first request. IIS configuration has the lookup order.

4. Verify. On IIS the module emits X-Page-Speed:

   (Invoke-WebRequest http://localhost/ -Method Head).Headers["X-Page-Speed"]

   Then open /pagespeed_global_admin on the server itself: the Configuration page lists the active filters, so you can confirm your directives loaded. Is it working? has the other checks.

5. Rename when convenient. pagespeed.config takes priority when both files exist in a directory; rename iiswebspeed.config to pagespeed.config at your own pace. No content changes are needed.

Common stumbles

• “Module DLL could not be registered” is almost always an IISpeed remnant: the old native module is still registered in applicationHost.config although its files are gone. Remove the IISpeedModule entry, run iisreset, and run the MSI again.
• Pages load but nothing is optimized. Check the rewrite level in your configuration (PassThrough optimizes nothing), a Disallow that excludes the site root, or an application pool identity that cannot write to the cache directory. The admin console’s Statistics page shows which: no image rewrites means the rewrite never ran; resource_url_domain_rejections points at a Disallow or domain mismatch.
• Combined resources return 404.11. combine_css and combine_javascript produce URLs with a +; allow double escaping in the site’s web.config. See IIS tuning.

Roll back

Uninstall the module from Apps & features, run iisreset, reinstall the IISpeed installer you kept, and restore your saved configuration files if you renamed them. Nothing on our side needs undoing.