Robin Lee Powell <rlpowell@digitalkingdom.org> wrote on 11/25/2010 01:12:50 PM:

> The problem is that calling
> "BackupPC_serverMesg BackupPC_nightly run" when the regular
> nightlies are already running, or calling it twice in quick
> succession, doesn't result in the scheduler restarting the nightlies
> run from scratch (GOOD) or queuing up a second nightlies run when
> the first finishes (not great, but OK), it results in the scheduler
> eating its own face (BAD).

Given your use case (free up space immediately), your "GOOD" and "not great" options are effectively identical.  The extant nightly will be some random amount through its process when you submit the second nightly.  It will then free up the space for the remaining amount of the pool.  Once it finishes and starts a new nightly, the new nightly will start at the beginning of the pool and make its way through it, freeing up the part that the existing one missed.

The only part of the process that is wasted when you run the nightly twice is the part where the second nightly job covers the part of the pool that was already processed by the first one after you submitted the second nightly job.  Restarting the nightly job from scratch will not change the amount of time that it takes to free up your disk space--not one instant.  It will, however, cause the nightly job to process some of your pool twice, *after* the disk space is freed up.

In the end, that doesn't seem like that much of a win.  So either way would work out to be practically the same.  I do agree that "eating its own face" is *not* optimal, however!  :)

Timothy J. Massey
Out of the Box Solutions, Inc.