Try a combination of Incremental and differential backups

Hello,

I have some troubles with the space used for my home machine's backup and
wondering if the following schema works:

1. I make a total backup in file FILEXX
2. I make a daily incremental backup, from Mon to Sat, in task N1 indicating FILEXX as the full backup
3. I make a weekly differential backup, on Sunday, in task N2 indicating FILEXX as the full backup.

Does it work? Can I combine this things in two different tasks and have everything recovered in case of a failure?

Thanks!

 

I’m not sure what you hope to accomplish.
Another INC on Sunday will only contain the changes since Saturday while a DIFF on Sunday will contain all the changes since Monday (or whenever the FULL was run). Where’s the space savings?

 

I'd stick with incs OR diffs. Don't complicate things. And I'd try to keep at least two full sets at any given time.

 

Also, if all the backup files are stored in the same place running a DIFF on Sunday may be the same as running an INC.
TI will see the FULL and all the INCs as a set and create a DIFF containing the changes to that set. The result would be the same as an INC.

 

OK, maybe I was not clear. Here is the situation:

At this point, I have to cleanup the external disk every 4 days to have
enough space for a differential backup.

Said that, the first action I took is to change it to incremental, but means
that will take longer to recover in case of failure. That is why I thought
to do a combination between inc and diff could be a solution to extend
the period for cleanup longer than twice a week

Thanks!

 

Sorry, I'm still not clear on why you want to do a DIFF in the first place after already doing all those INCS. Run one more INC and you'll be able to restore to any day of the week. That DIFF will not save any disk space as explained earlier.

"but means that will take longer to recover in case of failure"

I doubt the time would be noticeable.

 

The answer to this depends on your backup requirements. If you need always to have the previous day backed up, then you could simply do a full every day and keep knocking the oldest off. Depending on space available this would give you the ability to restore any of the last three or four days. (You could substitute diffs or incs for days 2, 3 and 4 but it would be messy to manage).

On the other hand if you could accept that your most recent could be up to three or four days old then you could just do two full and two diffs a week.

But if you really need a backup every day and X days of history then get a bigger disk, size a function of X.

 

One scheme I use is to create a set of scheduled tasks using the following 3 backup file names; MonTue, WedThr & FriSat.
A FULL gets created on Mon and then on Tue an INC gets appended to it. Then another FULL on Wed with an INC added to it on Thr. Same for Fri & Sat.
Then I wind up with the ability to restore to any day Monday through Saturday but I use less disk space than if I ran a FULL each day.

 

That's a good system. For myself, I now do only full backups since hard drive space is now so cheap. I recently bought a Western Digital external USB hard drive, 500 GB, for Canadian $120. That can hold a lot of full backups and synced files.

 

I too use only FULLs when possible. The scheme I use on a different box (which I've posted before) is as follows:

I have 9 scheduled tasks, all Full images.
One each for the 1st, 8th, 15th, 22nd and 29th.
A Weekly each Sunday.
Then three more, one each on Mon & Thu, Tue & Fri and Wed & Sat.
Once these 9 images are created, they just cycle through and get written over.

I will run a quick INC if I'm about to add or alter something major, but otherwise it's FULL all the way.