HTTP Compression and the Vary Header
We have an Virtual Server which has the oracle_as_http-wan-optimized-compression http profile assigned to it. The default compression values are set to a minimum of 1024 bytes. It also has the 'Vary' header insert ticked.
The problem is this. If any objects under 1024 bytes pass through, they are not compressed, but the Vary header is added anyway, which seems kind of pointless to me, as a proxy server would never receive this object compressed, and therefore why would it need to have a variance for accept-encoding on the hash and keep two copies possibly.
The bigger issue, is that due to the way IE6-8 works, if they receive a uncompressed object that has a Vary header included, it will not cache it. This is causing performance problems for our high latency users, and i need to fix it.
I could lower the compression minimum threshold, which could end up increasing the latency of certain low size objects. I could remove the Vary header altogether would could provide an issue with any proxied connections. Or, could I disable the HTTP profile Vary header insert and write an iRule which checks the object size and then either adds it or doesnt?
I am raising a Support Case on the issue itself as i dont believe the LTM should be adding this header when the content is clearly not going to be compressed, but any help with the iRule or alternative options would be appreciated.