File attributes

[perjonsson1960]

Folks,

Which attributes are B&R using to determine if a file in a Windows machine/VM has been changed since the previous backup, in order to know if the file should be included in an incremental backup or not?

Regards,
PJ

[wishr]

Hi Per,

Take a look here and here and let us know if these sections answer your question.

Thanks

[perjonsson1960]

Thanks!

I know that B&R uses CBT, but it didn't spring to mind when I was pondering about it this morning...

PJ

[wishr]

No worries

For backing up VMs and physical machines we use various CBT technologies since it's an image-based backup. However, for NAS backup the approach looks very similar to what you mentioned in your question and we use CRC for that.

Thanks

[perjonsson1960]

One more question:

If a file that has been backed up by B&R gets overwritten by an identical copy from another source, does B&R think that NO blocks have been changed, or that ALL blocks have been changed?

PJ

[wishr]

With VM and Agent backups it purely depends on whether the blocks have changed or not. I can imagine both situations.

[perjonsson1960]

I ask because we are currently copying all files and folders from an old file cluster to a new one using Robocopy. About a week ago I backed up the new cluster with B&R, which went well. It is about 15 TB of data. A few days later a colleague started a new copy process with Robocopy, thinking that it would copy only files that have been modified or created since the previous copying, but now he says that it seems that ALL files are being copied once again. So I was wondering, when I run an incremental backup after the new copying is done, if B&R will think that all files have been modified and pretty much does a full backup, even though it technically is an incremental backup...

[wishr]

To clarify, what Veeam technology you are using to back up the file cluster? VM backup, Agent backup, or File share backup?

I should say in advance, that it's hard to answer this question because it depends on how you copy the files, the type of the file system, how the blocks are handled by the file system, CBT, and other factors. All these factors one way or another have an influence on the outcome.

[perjonsson1960]

The cluster is physical, so it is an Agent Backup and the Volume CT Driver is installed. In the backup job the "Failover cluster" type is used, and the AD cluster object is used in the "Computer" section. The backup mode is "Entire computer", and a SOBR is used for storage.

[wishr]

Got it. If the file system of the storage where you are copying the files writes your data to "new" blocks during the copy operation, the blocks will be backed up during the next incremental agent job run.

By the way, since it's a file server, why you are not using our File share backup capabilities?

[perjonsson1960]

Quite frankly, I wasn't aware of it. Is it wrong to use the Failover cluster scenario? Is it better to use File share backup? And if so, why? I am familiar with Failover cluster backups, and I think they work well.

[wishr]

No issues to use agents to back up a failover cluster, especially if you are interested in backing up the OS itself and installed applications.

However, if you are interested in backing up files themselves on a NAS share (SBM or NFS), you may want to give File share backup a try. Speaking about benefits, there are multiple, but the main are backup speed, storage savings, unique approach to file versioning, compliance, simplified and quicker recovery. You can find more information and the solution brief by this link.

[perjonsson1960]

Thanks!