[Samba] Samba and Preallocated Files

Jeremy Allison jra at samba.org
Tue Mar 15 18:00:01 GMT 2005

On Tue, Mar 15, 2005 at 06:31:19AM -0500, AndyLiebman at aol.com wrote:
> A question about capturing videos to a Samba  share... 
> When Apple's Final Cut Pro captures video files, it  pre-allocates file space 
> on the destination volume. 
> If you capture to a  local volume that's physically attached to a Macintosh, 
> or if you capture to a  network volume via AFP (Apple File Sharing Protocol), 
> you can see that Final Cut  instantly creates a file of the anticipated size 
> on the destination volume at  the moment just before capture begins (the 
> anticipated size is based on the  maximum capture time limit set by a user). 
> However, when capturing  videos to a Windows or Samba share, Final Cut 
> actually will write out "dummy  data" to a file, and then presumably it replaces the 
> dummy data with real data  as the capture moves along. 
> Effectively, this makes Samba and Windows  shares useless for capturing Final 
> Cut videos. Because, for instance, if you  expect to capture a 20-minute DV 
> clip, it will take approximately 10 minutes to  create the pre-allocated file 
> before capturing even begins -- even when you are  connecting via a dedicated 
> Gigabit Ethernet link. The process seems to chug  along unbelievably slowly. 
> And if you were capturing uncompressed video (which  has about 5x the data rate 
> of DV video) well, the wait would be interminable.  
> Can anybody on this list see a way to allow Final Cut to instantly  create 
> that pre allocated file space that it wants to create on a Samba share?  Are 
> their any Samba settings that could make this possible? It would be a coup  for 
> Samba! 
> BTW, Apple's IMovie doesn't go through this pre allocation  business. But, 
> alas, IMovie doesn't capture timecode data, so Final Cut users  who want to work 
> with Samba shares can't simply switch to IMovie for capturing  their videos. 

That's a Mac client issue. We do support "sparse" pre-allocation on the
server side. I'd raise it as a bug with Apple.


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