Tux3: the other next-generation filesystem

What is that, and how does it work? I'm curious...

In general, I don't see how replication can help in the situation I encountered -- basically, some data on the disk magically changed without OS intervention. The only way to distinguish between that and a real data change is if you are somehow hooked into the OS and watching the writes it issues. Maybe ddsnap does that?

>It is not milliseconds, it is a significant fraction of your CPU, no matter how powerful.

Can you elaborate? On my year-old laptop, crc32 over 4k-blocks does >625 MiB/s on one core (adler32 is faster still), and the disk with perfect streaming manages to write at ~60 MiB/s, so by my calculation the worst case is 5% CPU. Enough that it could matter occasionally, but in fact seek-free workloads are very rare... and CPUs continue to follow Moore's law (checksumming is parallelizable), so it seems to me that that number will be <1% by the time tux3 is in production :-).

No opinion on volume manager vs. filesystem (so long as the interface doesn't devolve into distinct camps of developers pushing responsibilities off on each other); I could imagine there being locality benefits if your merkle tree follows the filesystem topology, but eh.

>If you want to rank the relative importance of features, replication way beats checksumming.

Fair enough, but I'll just observe that since I do have a perfectly adequate backup system in place already, replication doesn't get *me* anything extra, while checksumming does :-).