Status: OUT
The B-tree's durability model protects user data but not structural integrity: mutations pay double fsync for data pages (WAL entry + data write) while structural metadata is never fsynced, AND structural integrity silently erodes during normal operation (leaked pages, ever-growing height, dangling parent pointers after free_page) with no defensive checks in the I/O layer to detect or prevent degradation.
Fsync asymmetry protects the values but not the tree shape, while the tree shape degrades monotonically — durability effort is precisely misallocated
Depends on (SL): btree-structural-integrity-silently-erodes, btree-mutation-fsync-is-asymmetric