1. A method executed by a computer of selecting a more fault tolerant erasure code from a plurality of erasure codes for use in a fault tolerant system, comprising: generating a plurality of Tanner graphs corresponding to the plurality of erasure codes; generating a set of preferred erasure codes by discarding an erasure code if the corresponding Tanner graph does not have at least one predefined characteristic, the at least one predefined characteristic including a connected characteristic in which every node of the corresponding Tanner graph is reachable by traversing edges of the corresponding Tanner graph starting from any one node; comparing fault tolerances of the set of preferred erasure codes based at least in part on the corresponding Tanner graphs; and selecting a more fault tolerant erasure code from the set of preferred erasure codes based on the comparison.