Load-balancing an asymmetrical distributed erasure-coded system

A distributed system comprising:

• a plurality of CDN servers and a larger number of assembling devices;
• some of the CDN servers operative to have different fragment-delivery bandwidth capabilities than the other CDN servers;
• the CDN servers configured to store erasure-coded fragments associated with segments;
• each of the servers configured to store at least one erasure coded fragment but less than the minimum data required to reconstruct the segments;
• and a plurality of assembling devices, each configured to obtain at least a majority of fragments required to reconstruct the segments from a subgroup of the servers comprising between two and less than the plurality of servers;
• wherein the system configured to deliver fragments at a bandwidth approaching the combined fragment delivery bandwidth capabilities of the servers, by selecting the servers of the subgroups based on a random or pseudo random selection algorithm weighted according to the unutilized bandwidth of the servers and essentially regardless of the number of fragments stored on each server per segment stored on the server.

A method comprising:

• distributing erasure-coded fragments associated with segments among servers not having the same fragment delivery bandwidth capabilities;
• after distributing the fragments, each of the servers receives and stores less than the minimum amount of fragments needed to reconstruct the segments, and the amount of fragments received and stored by each of the servers is essentially not a function of the fragment delivery bandwidth capability of the server;
• selecting, for assembling devices, subgroups of servers having enough unutilized bandwidth to provide fragments;
• and approaching the combined fragment delivery bandwidth capabilities of the servers by pulling, by the assembling devices, erasure-coded fragments usable to decode segments, each fragment pull request associated with a specific segment, wherein each assembling device is retrieving the fragments from each server essentially independently of the bandwidth capability of the server.