Hi Loic, I looked at that some time ago. Table 1 in the paper says it all: If you care about decoding and reconstruction of data it gives a good improvement. If you care mainly about encoding speed, it is not the optimal choice (+72.1%). The algorithm optimizes the reconstruction of data units. This is relevant if your read-size is typically smaller than the block-size e.g. you encode 4 MB objects and you read 4kb pages. With normal EC you get a read amplification of K*4k if a data stripe is down, while with hitchhiker you get only 2/3 of that traffic in case of (10,4). The most interesting to implement is probably Hitchhiker-XOR+, which you have to combine with a Vandermonde matrix, it requires that the first parity is just the xor of all data chunks. So, yes, there is certainly a benefit in implementing that compared to other approaches (Xorbas,LRC) since it does not involve a space overhead and opens the door to use larger K values and save space! Cheers Andreas. -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
