Superblocks   The Superblocks section claims Superblock mirrors are kept at fixed locations  KiB into every block device with additional copies at  MiB  GiB and  PiB When a superblock mirror is updated its generation number is incremented At mount time the copy with the highest generation number is used All superblock mirrors are updated in tandem except in SSD mode which alternates updates among mirrors to provide some wear levelling  And httpsbtrfswikikernelorgindexphpUserWtachiOndiskFormatSuperblock claims Note that btrfs only recognizes disks with a valid x  superblock otherwise there would be confusion with other filesystems   I havent seen any relevant information in httpbtrfsipvde indicating anything about the current state of superblock use  In old link  now seemingly defunct but still cached by Google  httpsossoraclecompipermailbtrfsdevelFebruaryhtml Chris Mason writes that  Yes SSDs are a big target of mine and so the parts that are not currently favorable for SSDs will be changed  The big problem right now is that btrfs writes to a fixed super block for every commit  That will change to a rotating set of fixed super blocks to lower wear and improve redundancy    Is there any information if btrfs still hammers the same fixed superblock locations  Is there any information about the implications that a broken primary superblock will make btrfs no longer recognize the disk implying that this single but constantly updated data structure is a singlepointoffailure  Is there any information about the implications for SSD wear leveling if no change has been introduced And especially how common is it that the SSD uses regionbased wear leveling in which each superblock will only rotate among a limited number of flash blocks of the SSD Or where the two first superblocks might even end up in the same wearleveling region