Certain embodiments described herein are generally directed to generating an updated version of an existing code block in response to a data update to an existing data block of a plurality of data blocks in a distributed multi-mirror erasure coding system. For example, in some embodiments, a first operation cost to generate the updated version of the existing code block by a first method based on the plurality of data blocks and the data update is determined. In certain embodiments, a second operation cost to generate the updated version of the existing code block by a second method based on the existing code block, the existing data block, and the data update is determined. In some embodiments, if the first operation cost is less than or equal to the second operation cost, the first method is used. Otherwise, the second method is used.