This is the second part of our series on HTTP Live Streaming known by the acronym HLS. In this post, we’ll cover what we’ve learned as we load tested the Adobe Media Server (AMS) HLS Live pipeline on contemporary server hardware. (We still plan to cover troubleshooting HLS, but it’s a deeper topic and we want to give it the depth it deserves.)
In an ongoing effort to help our customers choose appropriate server resources for Adobe Media Server, we built a dedicated load testing suite for this important live video pipeline.
As we considered various test scenarios, we decided to test a single bitrate HLS live stream (1500kbps) as we believe it represents a worse-case scenario for scalability (vs. multi-bitrate). Additionally, the server hardware was running both AMS Core and Apache—together these are often informally just referred to as the AMS server. But, for HLS Live, Apache modules are doing much of the heavy lifting.
The flexible HLS Live load testing application we built allows us to:
- Run tests with any number of HLS Live playbacks
- Substitute any of the AMS config files with new ones with new config values
- Substitute any supported media file for live playback
- Substitute new clouds beyond our initial work with Google Cloud and Packet.com
Our preliminary results from this load testing application show that a server like the one shown from Packet.com can safely support 1500 concurrent playbacks for AMS HLS Live. In user terms, this represents 1500 users coming to your live event around its start time, staying for 30+ minutes, and getting a high quality stream with near zero buffering.
CPU 4 Physical Cores @ 2.0 GHz (1 × E3-1578L) Memory 32GB DDR4-2400 ECC RAM Storage 240 GB of SSD (1 × 240 GB) Network 10 Gbps Network (2 × INTEL X710 NIC'S IN TLB)
We’re excited to put this load testing application to further use with additional cloud hardware services, higher-quality streams (seeing AMS serve a 4K60p video live at high scale was fun for the team!), etc. We’d love to hear what kinds of questions you’d want us to answer with the app. Finally, if you’d like further details of our load test that provided 1500 concurrent HLS Live playbacks, we’d be happy to share them.
Catch us at this address [email protected].