<b>The course platform whose videos never cached</b>

<b>The course platform whose videos never cached</b>

An online course site in Dublin streamed lecture videos and saw a 30% cache-hit ratio on a library that barely changed. Lectures are static, so the number made no sense, until we watched the requests. Players issued byte-range requests, and the CDN cached each range as its own object, missing constantly as students skipped around.

We enabled byte-range caching with origin fetch on full segments: the edge pulls and stores the whole file once, then serves any range from it. The first viewer of a lecture warms it for everyone.

Video cache-hit ratio climbed 30% to 97%. Origin egress for video fell 88%, cutting roughly $1,900 a month. Seek-to-play time across Europe dropped from 800 ms to 60 ms because ranges came from the edge, not Dublin.

The number that mattered: 97% of video bytes never touched origin.