Full followed only by differentials - but only need to keep some differentials

There is a setting to specify the number of differential backups, the default is 5. You can also specify the number of complete sets to be kept as well as the max time a set is to be kept. The accepted wisdom is to keep the number of incremental backups small, as a problem with any one of the renders all subsequent one useless.

So you would need to set it to save the most recent 2 backup sets and specify the desired increment - I would recommend going with the default. If you are concerned about the time period covered, you could change it to 4 backup sets which would give you the same coverage.

Long version chains have been know to work. I once recovered successfully from a chain with 60+ incremental backups - no idea how it got configured that way; may have been a peculiarity of ATI 2014. But, I was incredibly lucky that all of the backups in the chain were OK.

Ian

You're mixing differential and incremental in your comment?

If I change to 5 differentials as an example, and retain only 2 sets, will is delete the existing many differentials that have piled up? I am hesitant to delete those manually, as I've seen that mess up ATI in the past.

Thanks for your reply.

Now that I clicked the # of differentials checkbox, I see all of the additional settings that were "missing". I don't adjust acronis very often so I had forgotten that those options, are not exposed until then.

Sim, ATIH only applies the automatic cleanup rules to complete backup version chains, so will not remove any unwanted differential backup images.

The way it works is that your # of differentials controls the size of the version chain, so if # = 5, you will create a new Full backup after creating 5 differential images, and when a version chain is cleaned up, it will be a chain comprising a Full plus your # number of differentials.

Automatic cleanup only runs after the next version chain has been started by the creation of a new full backup.

Thanks Steve. I went ahead and used the default 5 diffs; delete version chains older than 7 days; auto cleanup is kept on.

I then ran the backup. I was surprised to see that it created a new differential, not a full. Ati did remove the many older diff backups; I now have one very old full, and 7 days of diffs.

Interpreting what you wrote against what I see, does it mean that the full will never be created here? Because the diff # will never be 5? My oldest remaining diff is named Disks CDEF_diff_b1_s52_v1.tib

I don't mind full resetting this backup job; I asked about revising vs recreating; how do I get this thing to run as it is currently spec'd?

Sim, can you post some screen shots of your actual settings for the backup scheme page?

One of the side effects of making changes to these setting is that it can reset the count so that you start counting to 5 again, but if you are already at s52, you must have had a different setting previously, i.e. to create only differentials after the initial full backup?

What you may need to consider doing, is to clone this backup task which will create a duplicate task with the same name but prefixed by (1) - then select a new destination folder (or sub-folder) for this cloned task.  Remove the task settings for the original task you cloned from, then you can rename the cloned task to something more meaningful, but best to try to keep the name unique (not the same as the original one).  Finally run the new (cloned) task to start a whole new backup chain with a new full backup then start your 5 differentials after that first run.

Yes I'd forgotten that under the "create a full version after x diff" setting a slew of options becomes available.

What I've done since the last post seems to have worked. I ran a few backups and they were all diffs. I then set it to "create full after 1 diff" and ran it again. It then created a full, and a scheduled diff. I've set it back to "create full after 5 diff"; maybe things will settle in now. And the older heap of diffs were tossed by ATI.

Sim, thanks for the update, sounds like you may have got this one sorted now which is good.