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    RE: page vs log, this distinction is getting blurred with new SSD-focused techniques such as the ones used in BW-Tree. The idea is, random reads are fast with SSD’s, so we can scatter-gather reads across log-structured storage to reconstruct a logical page from fragments. This also means we don’t have to rewrite entire pages at a time for tiny writes.

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      Don’t most SSDs require rewriting data at the sector size anyways (which is what a page often turns out to be)? In a COW filesystem like ZFS, it ends up doing the recordsize (configurable) anyways + metadata, I don’t know what this means for the future of drives like Optane.

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        Yes, but for systems like the BW tree, that entire sector could be filled with new updates for different pages.

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      Fun fact: log-structured file systems were originally designed to improve write performance of hard drives. They later turned out to be great for flash-based media as well as the garbage collection always frees and re-uses large blocks at once.