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Comment by skybrian | Hacker News Reader

Since machines can crash, possibly corrupting data, it seems like you still need replication? The network might be the new bottleneck.

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Journal files. You can begin a transaction, crash, and lose the transaction. But the thing itself will be consistent.

Perhaps there's something funny about the failure modes of non-volatile memory that's different than a disk. Replication can improve things, sure. there's always a chance of a cosmic ray doing something weird to your stuff. That's (so far) a lot less common than a regular old crash.

I was thinking along the lines of the machine being on the wrong side of a network partition and then disappearing entirely. Cloud services are supposed to survive the loss of any single machine.

Ah, i think you're right, but that's a different problem. The Jepsen talks are enlightening, as so many errors get highlighted. Ultimately, if your algorithm is right, the hardware won't matter at all. Each node could be a person with pencil and paper, and the messages are lossy paper airplanes.

The NVM stuff (i think) just changes parameters to cache size, journal log size, stuff like that. I mean, it's cool tech, and it'll probably make stuff faster. But the reliability comes from the architecture and faithful implementation.

That's correct, the DBMS will rely on replication to survive media failures. The "NVM Express over Fabrics" standard is a step along that direction.

http://www.nvmexpress.org/wp-content/uploads/NVMe_Over_Fabri...

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