Setup guide

5 Save and close the configuration file.
6 Restart Stone and Wire: /etc/init.d/stone+wire restart.
Use multi-threaded direct input output
Most filesystems perform best when the I/O is parallelised across multiple threads/processes and sent
asynchronously. This allows the device to buffer I/O operations and reorganize requests for optimal
performance.
Some applications perform better than others on the same storage device, based on how they perform their
I/O. Applications that use single-threaded buffered I/O can be slow.
Your Creative Finishing applications use multi-threaded asynchronous direct I/O when capturing, playing
back, and performing other I/O intensive operations.
Make sure that any third-party application you use in conjunction with your Creative Finishing application
or to handle your media files uses direct I/O. This prevents needless CPU-intensive in-memory data copying,
thus maintaining optimum storage performance and freeing resources for your Creative Finishing application.
Enable media pre-allocation
By default, disk space for video files is allocated on-the-fly as the files are rendered or written. Concurrent
I/O operations from multiple clients or background processes can generate frames with poor locality of
reference, which leads to clip fragmentation and decreases playback performance.
To prevent this problem, Stone and Wire provides media file pre-allocation mechanisms that reserve the
necessary space on the disk before the actual writing of the media files takes place. Pre-allocation reserves
as many available contiguous disk sectors as needed for the file sequence to be written.
Depending on the filesystem you are using, you may choose between two media pre-allocation methods.
FALLOCATE The disk space needed for the file is allocated and filled with zeroes. On most filesystems, the
performance impact of this operation is as serious as when writing the actual file.
RESERVE The disk space needed for the file is reserved, but not written to. The apparent size of the frame
remains zero. This operation is much faster than FALLOCATE, but is supported only on certain filesystems,
such as XFS.
By default, pre-allocation is turned off in Stone and Wire (the method is set to NONE). In order to enable it,
you must modify a parameter in the stone+wire.cfg configuration file.
NOTE This is not a global setting. Pre-allocation must be individually enabled for each partition.
To enable media pre-allocation for a partition:
1 Open the/usr/discreet/sw/cfg/stone+wire.cfg file in a text editor.
2 Uncomment thePreallocation parameter in the section that configures the respective partition (for
example [Partition7]).
3 Change the parameter value from the default NONE to the pre-allocation method you want to use. For
example: Preallocation=RESERVE
4 Save the configuration file and restart Stone and Wire.
72 | Chapter 6 Software configuration