Status: OUT
B-tree mutations pay double fsync costs for user data (WAL entry + data page) but skip fsync entirely for structural metadata, creating an asymmetry where key-value pairs survive crashes but the free-page list and allocation state may not.
User data gets two fsyncs per mutation while metadata gets zero — a durability asymmetry hidden from callers
Depends on (SL): btree-double-fsync-per-mutation, btree-single-file-avoids-dir-fsync-gap, write-meta-no-fsync