Solutions to Common Problems

The following tips address some common issues.

QuickTime Reference Movies

If you submit a reference movie for distributed processing, the Apple Qmaster distributed processing system will automatically copy the appropriate media files to the processing cluster. For the best performance, you can avoid this file transfer step by making sure that the media files specified in the reference movie are available to each node of the Apple Qmaster cluster. For more information, see How the Apple Qmaster System Distributes Batches.

Cluster Settings for Extended Transcoding Sessions

If you anticipate a transcoding session that will last up to seven days or longer, you must make an adjustment in the Advanced section of the Apple Qmaster preferences pane. By default, temporary process files may remain on a cluster’s scratch location for seven days before they are automatically deleted. You can increase this value (the number of days) in the Apple Qmaster Sharing window of Compressor.

Cleaning Up Cluster Storage

If you are using cluster storage and an error occurs, partial files may be left on the designated cluster storage location. Check the designated cluster storage location to make sure no partial media files are left there. If you find partial media files, delete them and submit the job again.

Using Apple Qmaster with an NFS Server

By default, Apple Qmaster uses /etc/exports to define its Cluster Storage export. This can cause a conflict if you defined an NFS export in your local NetInfo database. When you enable a controller using Apple Qmaster 2 or later, Apple Qmaster uses /etc/exports, not entries defined in your NetInfo database. To work around this issue, either move the exports to /etc/exports, or move the controller to a computer that doesn’t export anything.

Apple Qmaster Distributed Processing and Xsan

Here are some tips on using the Apple Qmaster distributed processing system with Xsan.

Restarting Apple Qmaster and Xsan

Using previous versions of Apple Qmaster distributed processing on an Xsan may cause mounting problems when restarting an Apple Qmaster distributed processing cluster controller.

Restart Apple Qmaster and Xsan computers in the following order
  1. Turn off the cluster controller by deselecting “Share this computer” and clicking OK in the Apple Qmaster Sharing window, opened by choosing Share This Computer from the Apple Qmaster menu in Compressor.

  2. Restart the Apple Qmaster cluster controller computer.

  3. Wait for the Xsan volume to mount on the desktop.

  4. Select “Share this computer,” select either “as QuickCluster with services” or “as Services and cluster controller,” then click OK in the Apple Qmaster Sharing window to restart the controller.

Xsan Compatibility

Xsan 1.3 is not compatible with Compressor and the Apple Qmaster distributed processing system when Xsan media drives are used for cluster (scratch) storage. To use Xsan with Apple Qmaster 2.3, update to Xsan 1.4.

To download and install Xsan 1.4

Compressor Command-Line Usage Requires Login

Although it is possible to use the command line to run an Apple Qmaster distributed processing network, each Compressor service node (each computer providing Compressor distributed processing services) must be logged in (with a Mac OS X user name and password) for full functionality.