"As alluded to above, this does introduce a separate challenge with multi-file consistency. The team took an interesting approach here. The index file points to

"As alluded to above, this does introduce a separate challenge with multi-file consistency. The team took an interesting approach here. The index file points to the location of the root of the page graph and free space map in each page cache file. When persisting a multi-file transaction, all page cache files are flushed to disk before the index file." That sounds familiar: https://pthree.org/2012/12/14/zfs-administration-part-ix-copy-on-write/ https://pthree.org/2012/12/14/zfs-administration-part-ix-cop...