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.
well, the inode64 option itself is the -inverse- of the hack, actually,
right. Default XFS inode allocation changed a few years ago, to force
inodes into the low 32-bit range. THAT was the mild hack, and the
inode64 option was added to again allow XFS to work as originally
designed, allocating inodes anywhere on the filesystem on systems which
could handle 64-bit inodes.