Azure Akamai CDN Compression

Dev S 26

Hi,

Does Azure Akamai Standard CDN perform compression on configured content-type files if "Large File Optimization" is turned on ?

We see that it compresses fine with "General Web Delivery", but, we get a 403 error when the file size is over 1.8GB. So, we tried changing optimization to "Large File Optimization" and this serves large files, but seems like it doesn't compress anymore?

Thanks.

ChaitanyaNaykodi-MSFT 23,106 Reputation points Microsoft Employee

2022-11-16T01:22:40.043+00:00

@Dev S
Thank you for reaching out. As per the Troubleshooting CDN file compression document can you please confirm if the request contains an Accept-Encoding header, and the value for that header contains gzip value?
As Azure CDN from Akamai profiles only support gzip encoding, this might be the reason the file was not compressed. Thank you!
Dev S 26 Reputation points

2022-11-16T01:53:03.08+00:00

@ChaitanyaNaykodi-MSFT

Yes, we are sending the Accept-Encoding Header and the value contains gzip. I can further confirm that we are getting back gzipped content when the Optimization for our Akamai Profile is set to "General Web Delivery". However, we have files which are larger than 1.8GB and therefore have to use Optimization of type "Large File Download". Setting this optimization serves large files but they are not compressed and this also turns off compression for files which are smaller than 1.8GB.

As per https://learn.microsoft.com/en-us/azure/cdn/cdn-improve-performance?toc=%2Fazure%2Ffrontdoor%2FTOC.json#azure-cdn-standard-from-akamai-profiles all files should be eligible for compression if the MIME-TYPE is set up for compression.

So, does switching to "Large File Download" turn off compression capability? If so, then it doesn't seem to be indicated in the documentation unless I am missing something, or, is it expecting some additional headers or configuration?

Thanks and looking forward to your response.