Effects of enabling Synthetic fulls

[itlad]

Hi all,

When using Veeam forward incrementals, what effect would enabling Synthetic fulls have on disk space?

E.g. If I currently have a 1TB VBK and 10 x 100GB VIB files.

Would I get another 1TB VBK if retention policy = 2

Thanks
itlad

[foggy]

Yes, synthetic full will create another ~1TB VBK file. The previous VBK file will be deleted along with the whole old VIB chain right after the next VIB file is created and you get the second restore point. To better understand the forward incremental backup mode, please refer to the corresponding section of the product user guide and this topic.

[itlad]

Thanks foggy
I suspected this would be the case
My problem is that a full backup + forward incrementals + a full synthetic backup at the end of the week simply won't fit on the NAS backup repository
The current NAS is also a simple RAID 1 which I don't believe would cope well with the IO of reverse incremental.
For now I'll leave it as full + forward incrementals and redesign it when we get a decent NAS

[lanzia]

What would be considered to be a decent NAS that can handle reverse icrementals.
I'm facing the same question at the moment. I have a QNAP TS-459U which acts like a repository.
I would prefer to do reverse incrementals but have no clue of it will work with the NAS.

[dellock6]

It depends on several elements:
- size of the VBK to be created (and later modified by the reverse incremental job)
- size of the daily amount of data created by the incremental run (to be injected in the VBK)
- speed of the NAS
- backup timeframe you can tolerate

With some analysis, all these values can be roughtly calculated, and there is also the possibility your QNAP is good for the job.

[itlad]

It depends on several elements:
- size of the VBK to be created (and later modified by the reverse incremental job)
- size of the daily amount of data created by the incremental run (to be injected in the VBK)
- speed of the NAS
- backup timeframe you can tolerate

With some analysis, all these values can be roughtly calculated, and there is also the possibility your QNAP is good for the job.

Hi Luca,

What would you think in my scenario:
* 1TB VBK
* 100GB incrementals would be created on a Tuesday and Thursday and need to be injected into VBK weekly
* The NAS would be a simple Iomega Storcenter IX2-200 (1GHZ CPU, 256MB RAM, RAID 1)
* Full Backups can run from Friday night to Monday Night (72hrs)

Thanks

[dellock6]

Uhm, wait, if you talk about weekly injection, that is synthetic full (possibly with transform), not a reverse incremental like other user. In reverse, injection happens at every run of the job, so it would happen on Tuesday and Thursday.
You talk about full weekly backup, so I would definitely assume you are going with forward incremental plus synthetic. This kind of job creates 3 I/O per bit (see this: http://www.vuemuer.it/wp-content/upload ... des_IO.pdf) so it's even heavier than reverse, and I suspect that NAS would have troubles in dealing with it.
Also, for forward incremental (does not matter synthetic or not...) you need to save at least two full backup for retention purposes (3 for the default 14 days retention) so you better test how much compression and dedupe Veeam can give you on the full backup, since it's a 1 Tb bunch of data. That Iomega I remember holds only two disks, right? So you better use at least 2 Tb disks. Think about the standard 14 days retention
(estimate 50% reduction) 500 Gb full * 3 retention points + 50 Gb * 4 incremental = 1700 Gb

My suggestion: start easy with forward incremental and only 7 days retention, and check how much space and time it takes for backups to complete, then you can adjust and extend you retention. You do not have so many I/O capacity from the Iomega, so you need to not kill it while running. Probably better to use simple forward incremental since your production storage is faster than the Iomega, so better load IO on it rather than on the Iomega...

Luca.

[itlad]

Great advice, Thanks Luca