Nope, previous block versions get GC'd. I don't see how LBAs have any relevance here... you're talking about a much lower layer than what Torus is operating on.

You're providing a block device interface to the container. The container's FS is addressing LBAs. Sequential reads to the container's adjacent LBAs get turned into reads to whatever random Torus node is storing the data, based on when it was last written...

Exactly what you said. Torus is exposing block on top of what could be described as a log structured FS. So while you may not know about LBAs, there are LBAs involved. I took a look at the code and you are putting a FS like ext4 on top of your block device. Any time an LBA is written to, you append to your store. This causes sequential access to become random, and in addition causes unneeded garbage collection issues.

Further more, it appears to me that etcd is now in the "data path" That is, in theory, each access could end up hitting etcd.

If so, I really would question why anyone would do this at all... this is not how any storage system is written.

The problem here is that you are trying to do block on a file system. This is a bigger problem than you can imagine and while you may think lbas are not involved, there actually are. You are naively taking on a well known area in storage