Target space estimates and failed transfer recovery

[RupeMart]

I'm new to Veeam Backup and Replication and have been experimenting with the evaluation version. So far, it's doing everything I need it to, but I have a couple of questions.

Is there a way to calculate the approximate amount of space required on the target, for USB disk for backup and second ESXi host for replication? While the GUI provides an estimate figure, I'm provisioning new servers and need to know how much of the disk to allocate to guests and to the backup and replication files. We have two ESXi v4 hosts which will each run 50% of the guest VMs, and will replicate between themselves, i.e. ESXi 1 runs A and holds a replication copy of B, and ESXi 2 runs B and holds a replication copy of A. This is for a small business that cannot afford enterprise level fail-over solutions, and Veeam seems perfect for this situtation.

Also, if I've started a backup or replication job, and a problem causes it to abort, what is the consistency of the backup and replication copies? Are they as good as the most recent successful backup and/or replication jobs, or do following backup and/or replication jobs need to run to be able to bring the data to a usable state?

I've searched the forums for "space", "estimate", "size", etc, and not found any information postings.

[Gostev]

Hello, there is a Disk Cost button on the Destination step of the job's wizard to calculate the approximate amount of space required on the target according to your selected data retention policy. It is worst-case ballpark approximation though, actual numbers may vary significantly depending on the actual workload your VMs run.

You can always restore or failover to any previous successful restore points in case latest backup or replication job pass was aborted. Subsequent job run will also automatically heal the "latest state" restore point of backup/replica file.

[RupeMart]

Hi Gostev, thanks for your reply and confirmation of recoverability. Re the disk cost, I was hoping for a formula, so I can size my virtual hard disks appropriately before creating them, rather than build a VM that's too large and have to rebuild. I guess that since a "rebuild" doesn't have to include the OS and software, but is just an allocation of the VMDK files, it shouldn't take too long...

[Gostev]

Rupert, the formulas we use for disk space estimation are the following:

Backup size = C * (F*Data + R*D*Data)
Replica size = Data + C*R*D*Data

Data = sum of processed VMs size by the specific job (actually used, not provisioned)
C = average compression/dedupe ratio (depends on too many factors, compression and dedupe can be very high, but we use 50% - worst case)
F = number of full backups in retention policy (1, unless backup mode with periodic fulls is used)
R = number of rollbacks (or increments) according to retention policy (14 by default)
D = average amount of VM disk changes between cycles in percent (we use 10% right now, but will change it to 5% in v5 based on feedback... reportedly for most VMs it is just 1-2%, but active Exchange and SQL can be up to 10-20% due to transaction logs activity - so 5% seems to be good average)

[dcolpitts]

I realized this is a very old thread, but I'm struggling to understand this formula and in particular, where/how the average compression / dedupe ratio is determined. When I look a client location that is currently utilizing v7, in order for the formula to give me what my physical disk usage currently is, I'm getting a average compress / dedupe ration of 12.8%. But when I look at the daily reports, I don't see this number listed anywhere - so assuming we wanted to calculate the target space usage at another client site and we install an eval of Veeam and run it a couple of days to get statistics so we can determine future growth requirements, how do I calculate the correct average compression/dedupe ratio?

I've already tried to track this down from the partner portal, and I don't seem to be getting any response from those who are responsible here in Canada for partner relations.

Thanks

dcc

[Gostev]

Just use 50% (0.5) for data reduction (C in my formula). This is good, safe estimate for the default compression setting.

[dcolpitts]

Gostev - while 50% is a safe estimate, what I want to know is how C is calculated based on existing backups and reports. I have a customer (who is not yet using Veeam, but will be shortly) requiring us to predict / extrapolate his backup storage requirements for the next 3 years based on his existing data.

I had a long chat with one of the Veeam SE last week, and I'm still as confused about this now as I was then - the only difference is that we now have a week's worth of backups of the customer's data with the trial version to try and figure this out. I would assume there is some way I can take the backup reports and calculate C out of those so I can accurately forecast the customer's storage requirements going forward once they start utilizing Veeam. I don't want to over build the storage solution for the customer, but I don't want to go back to him in 24 months and tell him we under-estimated the storage requirements and he needs to add more.

Thanks

[veremin]

What about using Veeam One in this case? It has Capacity Planning section for the repository that shows the number of days before the repository runs out of free space. It extrapolates the data, using historical information.

Thanks.

[BHB3805]

Veeam One supplies a report, Capapcity Planning for Backup Repositories.
I'm not sure how to calculate increamental and full backup requirements with this report.
We are trying to determine additional target storage is required to move from 30 days of backups (synthentic fulls on a weekly basis) to 60 days and 12 end of month backups.

[dubvr6]

Hi

I am trying to verify the above back up formula by using the stats from a working VM, the following are the details:

VM size is 140GB
Dedupe: 1.0x
Compression: 2.1x
Retention is default at 14

Please can someone workout backup size using the above formula and show the working out.

Thanks

[foggy]

Your previous post was merged into another discussion regarding space calculation, please review.