Desktop Edition 15.6.1 gets multiple activity threads—but be careful

[DavidHertzberg]

Retrospect Mac administrators,

Based on the discovery by JamesOakley that "under 15.x for Windows, even Desktop edition gets multiple execution units,"  I was able to verify that the same is true for "activity threads" under Retrospect Mac 15.0—using the test version Retrospect Tech Support had given me for diagnostic logging of -530 bugs.  (I still run production backups using the Retrospect Mac 14.6 "backup server" and the 14.1 Client, because later versions disable my -530 workarounds.)  The new feature, of course, is simply a disabling of the Desktop Edition code that previously reset the number of units/threads to 1 every time the Engine was started—thus forcing Desktop Edition to mimic the non-multithreaded Retrospect Windows/Mac 6. 

However when the Retrospect Inc. engineers corrected Retrospect Windows 15.1 so  that "Fixed: Desktop can now reduce its maximum execution units (#7317)", they didn't look at the Retrospect Mac 15 Console.  Running Retrospect Mac 15.6.1, if I set General->Preferences Allow n Activity Threads to set n lower than 16, it snaps back to 16 whenever I reboot my "backup server"—thus restarting the Engine.  However if I merely quit the Console and then restart it again, that preference stays where I set it.

I'll file a Support Case.

In the meantime, use this new capability carefully. Make sure that any script you run specifies Activity Thread 1, unless you known darned well that that script can safely run in parallel with any other script that can possibly be running at the same time.  Retrospect will not allow you to do more than one Backup with the same Media Set as a destination simultaneously, nor will it allow you to do more than one Backup with the same drive as a source simultaneously—unless different Favorite Folders within the drive are being backed up.  However I discovered two years ago that Retrospect will allow you to overlap a Backup script and a Copy of the Backup script's destination, causing a problem—described in the second substantive paragraph of this post—that will continue to exist until the Retrospect engineers add a modest enhancement I proposed in the remainder of that post—an enhancement they have not done yet.