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by eivanov89 809 days ago
In YDB with block 4+2 erasure coding, you need half the disk space compared to mirror-3-dc schema. Meanwhile CPU usage is just a little bit higher, thus in high throughput tests mirror-3-dc wins. Indeed as mentioned in the post there might be a tail latency win in latency runs, but if your task is throughput with a reasonable latencies, replication might be a better choice.
2 comments

If you only care about throughput, just fetch the data and read should be the same speed as triple replicated.

For writing, triple-rep has to write 2x as much data or more, so it's going to be slower unless your CPUs are horribly slow compared to your drives.

I expect it to save a lot of CPU by only needing 1/3x of compactions. You might want to do a benchmark on that ;). An example is quickwit (building inverted indexes is very expensive).