Media Flow Controller Overview : Media Flow Controller Functions : Hierarchical Caching

Hierarchical Caching
When Media Flow Controller fetches data from origin upon cache miss, it caches the data in its local disks. Media Flow Controller implements an hierarchical caching mechanism that allows it to serve up to 10Gbps of data with just 16GB of RAM and a combination of SSD, SAS, and SATA storage. Media Flow Controller has its own optimized storage sub-system in which data is placed intelligently so it can be read back for very fast delivery to end-users.
Media Flow Controller organizes data in a hierarchical fashion using a cache tier manager that dynamically calculates the “hotness” of the data and places it in the right cache tier (see ““Hot” Content (Short Tail vs. Long Tail)” on page 29 for explanation of hotness). RAM is the highest tier, followed by SSD, SAS, and SATA, in that order.
The disk speeds are calculated and assigned to a tier in the cache hierarchy as part of the initialization of Media Flow Controller. When data is accessed from origin, it is stored in the lowest cache tier, and promoted to higher cache tiers as the hotness of the data increases. All this is done automatically by Media Flow Controller.
Additionally, Media Flow Controller allows you to set cache ingestion and promotion parameters (cache-ingest size-threshold and cache-promotion hotness-threshold) via the analytics command to create policies for when to ingest, or promote, hot objects to cache or the next highest cache tier, respectively. See “Terminology” on page 28 for definition of “ingest.”
See Figure 3 next, for an illustration.
Figure 3 Media Flow Controller Cache Ingest and Promotion Process

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Media Flow Controller Administrator's Guide and CLI Command Reference
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