Re: Ext3 vs NTFS performance

Theodore Tso
2007-05-02T19:35:13Z

On Wed, May 02, 2007 at 11:08:10AM -0700, Jeremy Allison wrote:
> > The right place is clearly Samba. I can't think of any other program
> > or filesystem protocol where writing a 1 byte write at 128k strides
> > would be used to signal a desire to do preallocation. In fact, it's
> > hard to think of a worse way of doing things.
>
> In fact they don't need to do this - there's an explicit CIFS
> set file allocation call to pre-allocate size they could use.
>
> There's a specific Samba VFS module that has XFS specific calls
> to do this - vfs_prealloc. - but this won't work on ext3.

Jeremy,

FYI, we are currently closing on a new system call so that
glibc's fallocate() will be able to call into the appropriate
per-filesystem routines in a portable way, since ext4 will have
persistent preallocation support.

I think we mostly have consensus on a calling convention which
all of the architectures (s390, power, arm, ia64, etc.); of course
then we will need to get glibc to support the new system call.

- Ted