On Mon, Nov 29, 2010 at 02:49:26PM -0500, David Teigland wrote: > On Wed, Nov 24, 2010 at 03:08:41PM -0500, David Teigland wrote: > > LOCK_MODE_NONE - the lock manager is unused, and it's up to the > > application to do its own locking or coordination when accessing the > > resource, e.g. if there's a clustered db or fs on the device that does its > > own coordination. You seem to be calling this SHARED, but there's > > actually no lock or exclusion that a lock manager would implement for this > > kind of usage. > > I failed to mention that with a more elaborate set of lock modes like a > dlm uses, the CW "concurrent write" mode fits the use case of leaving the > coordination to the application. Simpler lock managers only support > Shared or Exclusive, of course, in which case "None" would apply. This kind of difference in capabilities between lock managers is a good example of why I only provide the disk sharing mode to the plugin API, and leave choice of locking mode to the plugin. Daniel -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list