Final Cut Pro: Notes for setting Scratch Disks on Xsan

This document discusses setting Final Cut Pro's Scratch Disk folders for multiple users on an Xsan volume. Numerous configurations are possible, but planning the Scratch Disk settings is an important consideration, as it may seriously affect the way that Final Cut Pro is able to access resources on Xsan.

• Don't designate the root level of the Xsan as a Scratch Disk.
  In general, the root level of the Xsan volume should be write-prohibited for Final Cut Pro users. If you do designate the root level of the volume as Scratch Disk, other users may see an alert message when opening Final Cut Pro that says:

  "Unable to set scratch disk. The selected directory is on write-protected or non-writable media."

• Don't share the same Scratch Disk location between two or more users.
  Ideally, each user should have a unique folder on the Xsan volume that will act as Final Cut Pro's Scratch Disk for that user. Permissions for a user's folder should be set to allow that specific user to have read/write access. While it is possible for multiple users to share a Scratch Disk, Apple advises against this configuration, as it may lead to unexpected behaviors.
  
  
• If using Final Cut Pro 6.0.1 and earlier, use POSIX. If using Final Cut Pro 6.0.2 and later, use an Access Control List (ACL).
  If you use an ACL to designate a folder's privileges with Final Cut Pro 6.0.1 and earlier (including Final Cut Pro 5.x), it might not perform as expected if set as a scratch disk, or may not be configurable as a scratch disk.
  
  Instead, for example, if you want to make a user's Capture Scratch folder readable, but not writable by other users, do so with standard UNIX file permissions, as opposed to an ACL.

If a user on the Xsan has set the Scratch Disk location to a shared folder, and other users are subsequently unable to open Final Cut Pro, or make changes the Scratch Disk location, delete the Final Cut Pro preferences for affected users, and then set the Scratch Disk in accordance with the guidelines listed above.

For more information on the topics discussed here, refer to the Final Cut Pro User's Manual, and to the Xsan Admin Guide.

This document will be updated as more information becomes available.