lkml.org 
[lkml]   [2005]   [Nov]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: what is our answer to ZFS?
On Tue, Nov 22, 2005 at 07:51:48AM +0000, Christoph Hellwig wrote:
> What is a '128 bit' or '64 bit' filesystem anyway? This description doesn't
> make any sense, as there are many different things that can be
> addresses in filesystems, and those can be addressed in different ways.
> I guess from the marketing documents that they do 128 bit _byte_ addressing
> for diskspace. All the interesting Linux filesystems do _block_ addressing
> though, and 64bits addressing large enough blocks is quite huge.
> 128bit inodes again is something could couldn't easily implement, it would
> mean a non-scalar ino_t type which guarantees to break userspace. 128
> i_size? Again that would totally break userspace because it expects off_t
> to be a scalar, so every single file must fit into 64bit _byte_ addressing.
> If the surrounding enviroment changes (e.g. we get a 128bit scalar type
> on 64bit architectures) that could change pretty easily, similarly to how
> ext2 got a 64bit i_size during the 2.3.x LFS work.

I will note though that there are people who are asking for 64-bit
inode numbers on 32-bit platforms, since 2**32 inodes are not enough
for certain distributed/clustered filesystems. And this is something
we don't yet support today, and probably will need to think about much
sooner than 128-bit filesystems....

- Ted
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-11-22 15:55    [from the cache]
©2003-2011 Jasper Spaans