Xsan: How to defragment data for multimedia applications
Symptoms
If you have media or render files stored on an Xsan volume that have become fragmented, multimedia applications may report dropped frames when you work with them. This can occur with any version of Final Cut Pro, Final Cut Express, iMovie, and Xsan.
Products Affected
Xsan
Resolution
Dropped frames issues occur as a result of degraded performance. Many factors can contribute to this, including file fragmentation. Xsan includes a file defragmentation utility that you can run from the command line. To defragment an Xsan volume, type this command in Terminal:
sudo /Library/Filesystems/Xsan/bin/snfsdefrag -rv <PathToDirectory>
...where <PathToDirectory> is the path to the directory where your media or render files are stored. Other factors that may contribute to dropped frame issues can be found in this article.
Note: It is also necessary to run snfsdefrag -dv after performing bandwidth expansion on an Xsan Volume.