[Samba] File growth behavior of Mac OS X and WinXP

Simon Hobson shobson-lists at colony.com
Wed Dec 22 09:19:01 GMT 2004

Victor Moran wrote:

>I have a MacOSX 10.3 machine and a WinXP machine that are being used to
>produce large video clips (@1gig).  After they are rendered and ready
>for playback, they are copied to the playout machines using a system
>that uses watch folders shared out over samba.
>The watch folder works based on file size.  For example, 40 seconds
>after a file's filesize stops growing, the system assumes the file is
>complete and starts moving the file onto the playout device.

A better way is to use temporary file names during the copy, and then 
rename it when complete (or copy to a folder and then move).

Eg :
copy <video_clip> to //server/share/<video_clip>_
move <video_clip>_ to <video_clip>

Watching program ignored files that end with "_"

Or :
copy <video_clip> to //server/share/incoming/<video_clip>
move //server/share/incoming/<video_clip> to //server/share/<video_clip>

Watching program ignores contents of 'incoming'.

There are other ways of course, such as adding a semaphore file after 
the file copy is complete and so on - but I prefer the above method 
as it is fairly simple to do at both ends, and the rename/move is 
near enough an atomic process as far as any watching process is 
concerned (the file is simply not there at all, then it appears and 
is known to be complete).


Simon Hobson MA MIEE, Technology Specialist
Colony Gift Corporation Limited
Lindal in Furness, Ulverston, Cumbria, LA12 0LD
Tel 01229 461100, Fax 01229 461101

Registered in England No. 1499611
Regd. Office : 100 New Bridge Street, London, EC4V 6JA.

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