| Great to see someone going into this. I wanted to do a simple LSM tree using io_uring in Zig for some time but couldn't get into it yet. I always use this approach for crash-resistance: - Append to the data (WAL) file normally. - Have a seperate small file that is like a hash + length for WAL state. - First append to WAL file. - Start fsync call on the WAL file, create a new hash/length file with different name and fsync it in parallel. - Rename the length file onto the real one for making sure it is fully atomic. - Update in-memory state to reflect the files and return from the write function call. Curious if anyone knows tradeoffs between this and doing double WAL. Maybe doing fsync on everything is too slow to maintain fast writes? I learned about append/rename approach from this article in case anyone is interested: - https://discuss.hypermode.com/t/making-badger-crash-resilien... - https://research.cs.wisc.edu/adsl/Publications/alice-osdi14.... |