xmlcodeIf you have had a chance dive into how the WebAccelerator module on an F5 BIG-IP unit works, then I am sure you have come across the globalfragment.xml file.  After upgrading from TMOS version 9.4.4 to 9.4.8, I recently had such an opportunity and have walked away from the experience having learned some interesting things.

For those who haven’t had a chance to examine the file at length, the globalfragment.xml file is basically a roadmap that the WebAccelerator module can read to know how to handle or classify different file types.  If you want the WebAccelerator recognize and classify a particular file type it would be good for it to be defined in this file.

If you take the upgrade path I mentioned above, it might be wise to make a backup copy of that particular file first.  The file can be found in the “/config/wa/” directory.  It is possible for that file to be overwritten during the upgrade and if you have custom entries defined in it… well you get the picture!

Unbeknownst to me, custom entries had been inserted into that file for .wmv files at some earlier date.  Shortly after the upgrade of course, .wmv files stopped streaming properly from virtual servers utilizing WebAccelerator based HTTP class profiles.  So I took the profiles off the virtual servers in question and contacted F5 Networks Support.  I was unaware of how the WebAccelerator module used the globalfragments.xml file until I was educated by an excellent F5 Networks Senior Network Support Engineer about it.

I added the entries back for the .wmv files, reapplied the HTTP class profiles that I had disabled during troubleshooting and everything worked like a charm.  The Engineer was also kind enough to create CR12834 to add .wmv files to the stock list of file types into future TMOS versions.  Thanks again to Dale Anderson for all your help!

If you are having trouble with certain file types after applying a WebAcceleration HTTP class profile then you might take a peek at the globalfragments.xml file and ensure the file type is defined correctly within.

This issue and the one mentioned in my previous post are the only two issues that I had from upgrading from version 9.4.4 to version 9.4.8!

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4 comments so far

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  1. Is that the correct CR#. If so, it looks to be related to an incontrol issue and not anything to do with
    the globalfragments file?

  2. Ooops.. sorry about that.

    F5 Networks Product Development is tracked a request to add this functionality as CR122760 and it was added in BIG-IP WebAccelerator version 9.4.8 for the 9.4.x software branch. The request to add this functionality is still being tracked as CR122760 for the BIG-IP WebAccelerator 10.x software branch.

  3. There were a few CR’s setup related to this. There were also a few created for adding different file types to the list by default. The one listed above is for real media files. I will see if I can find the CR’s directly related to this issue in my e-mail stack….

  4. […] GlobalFragment.xml – From TMOS 9.4.4 to 9.4.8 […]