Which backup method should I choose?

[pufferdude]

I've read various threads here to try and figure out which backup method I should be using for my situation, but I still don't think I'm "getting it" completely. Here's the situation:

Been running Veeam for years using all Reverse Incremental jobs to a cheap NAS (QNAP) without issue... jobs all ran and completed within my backup window and everything was great. Then I replaced our primary SAN and in the process rebuilt the vSphere hosts and in THAT process ended up tweaking jobs (because VMs moved) and actually started looking at the logs again (which I hadn't done in quite a while... just cared about pass/fail emails.)

Anyway, I noticed that the incremental performance of the daily backups was quite poor... around 7-8MB/s but when I did a full I would get 30+ to the same storage. THAT's when I came here and learned that reverse incrementals are really hard on the backup storage, particularly cheap NAS. So I got the bright idea to switch everything to forward incremental with synthetic fulls once a week.

That's where I am today, but NOW I see that I'm keeping multiple "fulls" for each backup with no end in sight. This obviously is NOT going to be possible with my limited storage. So I then read up on the "transform" feature and it looks like it fixes the problem of keeping fulls around... but IT TOO is supposedly I/O intensive...

...so all of that brings me to my actual question. Since I was hitting my backup windows even with the lower-performing reverse incrementals, should I just go back to that? Or should I keep using forwards but also enable transforms? And would transforms be just as "bad" on the storage I/O as just doing reverse incrementals in the first place, so it's pretty much a wash?

As you can see I have some lack of understanding which is the best type for my situation. I'm trying to balance backup performance with keeping as little as possible on the storage (multiple fulls for any length of time would kill me) . I also don't understand what happens to the fulls when doing forward incrementals... do they just pile up forever? Any advice appreciated.

[Vitaliy S.]

Hi Jim,

That's where I am today, but NOW I see that I'm keeping multiple "fulls" for each backup with no end in sight. This obviously is NOT going to be possible with my limited storage. So I then read up on the "transform" feature and it looks like it fixes the problem of keeping fulls around... but IT TOO is supposedly I/O intensive...

There is an existing topic that has a detailed comparison of all modes in terms of I/O operations, please check it out: Reversed incrementals vs. Fwd w/ DAILY Synthetic + Trans

As regards your case, then forward incremental with active fulls sounds like the most optimal solution, however you cannot keep multiple full backups on the target storage due to the lack of free space. Given all these facts, I would suggest switching back to reversed incremental backup mode, as it allows keeping only 1 full backup at a time and is not that stressful as forward incremental + transform.

]I also don't understand what happens to the fulls when doing forward incrementals... do they just pile up forever?

No, they don't, please take a look a this topic for the answer: Job Set for 14 Mount Points - 46 exist

Hope this helps!

[pufferdude]

Thanks, that helps. I think I will indeed switch back to reverse incremental as they are so much simpler and space-efficient, and I wasn't having trouble getting the backups completed within the window.