Good to know. Thanks for the explanation. Basically ZFS maintains a ZIL based in-memory tree for the recent updates and a on-disk btree for the complete updat

Good to know. Thanks for the explanation. Basically ZFS maintains a ZIL based in-memory tree for the recent updates and a on-disk btree for the complete updates, minus the recent updates in ZIL. That's consistent with most database transaction log implementation. Some newer approach adds a Bloom filter to do fast decision between looking in the in-memory tree or in the on-disk btree.