Monthly Backups

[norelco]

Hello

I did start asking this on Twitter but replies limited to 160 chars means lots of messages!

I'm trying to figure out the best way to have daily backups in 7 restore point retention (so a week) and monthly backups of the same set of VMs keeping 12 restore points (so one years worth).

I understand that if this was going to tape, you'd do an active full then copy that off to tape with a script. In this scenario, all this will be kept online on disk so needs to take minimum amount of space. I understand I should have two separate jobs, one scheduled for daily one for monthly. To keep storage utilisation low, can I use incremental backups on the monthly or is this not recommended as they'd be a lot of changes to track in a whole month I guess.

Dave

[foggy]

Dave, you can use monthly incremental backups, no issues with that. Moreover, with forward incremental mode you will have to offload to tape only changes, which are always less than a full VM data. However, take into account, that with forward incremental mode, the number of fulls stored for the job for the given retention differs in time, so generally forward incremental mode is more space demanding.

[chrisdearden]

hi Dave - thanks for posting on the forums , I think I had misunderstood that you wanted to run a job yearly ( once a year )

If all of this data is staying on disk , you can run a reverse incremental with 12 restore points. Over a month , you'll have a fair bit of changed data ( if you do reverse incremental today - look and see how big a day's worth of change is , then multiply that by 30 ! )

[norelco]

Hi Chris

Actually the requirement is for both Trying to replicate an existing policy with daily, monthly and yearly backups.

So... if a full backup is 1.4Tb and we see about 40Gb of change per day then change per month is roughly 1.2Tb on 30 * 40Gb (although I guess it's quite likely that the same files are edited over and over again so this isn't strictly true...). So, on that basis..

Month 1: 1.4Tb on disk
Month 2: 1.4Tb + 1.2Tb on disk
Month 2: 1.4Tb + 1.2Tb + 1.2Tb on disk

Not much advantage to using incremental on the monthly backups... I guess the problem is amplified on the yearly backups... again, it's difficult for me to estimate the actual change data over the course of a year.

Dave

[chrisdearden]

what sort of storage are you using ? If your full backup is not huge , something like windows 2012 dedupe might help out for that long term retention.

[norelco]

Undecided on storage at the moment, still trying to scope this out really... It's likely to be either some big SATA disks on the SAN (not dedupe capable) or some big disks on an existing backup physical server. Current estimate based on daily reverse incrementals (keeping 30 restore points), monthly fulls (keeping 12 points), year fulls (keeping 5 years) is the following on disk

Daily Job - 2.5Tb
Monthly Job - 15Tb
Yearly Job - 6Tb

The big chunk is the combined 21Tb of data in the Monthly and Yearly full backups jobs. I'll have to look at dedupe in the storage then as that could be a big win storage wise

Dave

[chrisdearden]

Lots of big cheap dumb disk on a DAS is a good start. aim for RAID 10 where possible.

[foggy]

I'll have to look at dedupe in the storage then as that could be a big win storage wise

Then here is a couple of topics for you to review, might be useful:
Best Practice for MS Server 2012 DeDup Repo
My server Windows Server 2012 deduplication results

[veremin]

You might still do it without running second (monthly job). Just schedule a specific PS script to be run on the last Sunday/Saturday. This script will be responsible for running active full backup, as well as, transferring the last .vbk file it to an external device.

How-to run full backup via PS console.

How-to copy the last full backup to an external device.

Hope this helps.
Thanks.

[norelco]

Just schedule a specific PS script to be run on the last Sunday/Saturday. This script will be responsible for running active full backup, as well as, transferring the last .vbk file it to an external device.

Yep, that makes sense but it's still generating a separate full backup file, which is fine except that we'll been keeping it all on disk so need to find a way to reduce the storage it is likely to consume. At the moment, it seems that a Windows server on each site with approx. 30Tb of storage is going to be the best bet. Chris' suggestion of using Win2012 dedupe is interesting.. We might be able to do it with less storage if we Win2012 de-dupe can pull off something amazing, but I'm not sure we have any level of certainty on that given the likely size of the data files (around 1.5Tb to start with).

[veremin]

Assuming that you’re going to utilize Windows 2012 deduplication, you’ll end up using forward incremental mode (since it guarantees higher deduplication rates) and performing active full backup on regular basis. Just tune up the Windows Scheduler such a way, so that, the produced full backup won’t be a separate one, but rather the one that is supposed to happen according to VB&R schedule.

For instance, choose Sunday as a day for performing full backup in the job settings; schedule a PS script (responsible for running job) via Windows Scheduler to run on last Sunday of the month.

Thus, on the last Sunday PS script will initiate a start of a given job, the job will check the VB&R schedule and ,according to it, will perform an active full backup. So, it won’t be a separate full backup, but an expected one.

Hope this helps.
Thanks.