Steve Lord wrote:
ino64 is a test option, it deliberately adds a large number to
inode values so that it is possible to test that the inode handling
is 64 bit clean without buying a few Tbytes of disk (which would
have been very expensive when the code was written). It should
not be used outside of testing.
inode64 is a hack to force xfs to keep inodes down in the start of
the filesystem where the inode numbers (which are disk addresses
really) do not overflow 32 bits. This is for systems which cannot
cope with larger inodes. There are also 3rd party backup
applications which barf on large inode numbers, networker was
the one I remember.
OK, got that backwards, inode64 says do not keep them in 32 bits,
inode32 says keep them in 32 bits.