Re: Ext3 vs NTFS performance

Christoph Hellwig
2007-05-04T09:46:13Z

On Fri, May 04, 2007 at 09:12:31AM +0100, Anton Altaparmakov wrote:
> Nothing to do with win32 functions. Windows does NOT create sparse
> files therefore it never can have an issue like ext3 does in this
> scenario. Windows will cause nice allocations to happen because of
> this and the 1-byte writes are perfectly sensible in this regard.
> (Although a little odd as Windows has a proper API for doing
> preallocation so I don't get why it is not using that instead...)

Which means the right place to fix this is samba. Samba just need
to intersept lseek and pread/pwrite to never allocate sparse files
but do the right thing instead. Now what the right thing would probably
be a preallocate instead of writing zeroes, and we need to provide the
infrastructure for them to do it, which is in progress currently.
(And in fact samba already does the right thing for XFS if you use
the prealloc samba vfs module, which AFAIK is not the default)