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    SubjectRe: BIG files & file systems
    On Wed, Jul 31, 2002 at 08:26:38PM +0100, Christoph Hellwig wrote:
    > On Wed, Jul 31, 2002 at 01:16:20PM -0600, Peter J. Braam wrote:
    > > Hi,
    > >
    > > I've just been told that some "limitations" of the following kind will
    > > remain:
    > >
    > > page index = unsigned long
    > > ino_t = unsigned long
    > >
    > > Lustre has definitely been asked to support much larger files than
    > > 16TB. Also file systems with a trillion files have been requested by
    > > one of our supporters (you don't want to know who, besides I've no
    > > idea how many bits go in a trillion, but it's more than 32).
    >
    > What about using 64bit machines? ..

    It depends on many things:
    - Block layer (unsigned long)
    - Page indexes (unsigned long)
    - Filesystem format dependent limits
    - EXT2/EXT3: u32_t FILESYSTEM block index, presuming the EXT2/EXT3
    is supported only up to 4 kB block sizes, that gives
    you a very hard limit.. of 16 terabytes (16 * "10^12")
    - ReiserFS: u32_t block indexes presently, u64_t in future;
    block size ranges ? Max size is limited by the
    maximum supported file size, likely 2^63, which is
    roughly 8 * "10^18", or circa 500 000 times larger
    than EXT2/EXT3 format maximum.
    - ClusterFS: (Braam et.al.): 64 bit block indexes ?
    System file size limitation, same as with ReiserFS.

    (Just to illustriate a few..)


    /Matti Aarnio
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