UrBackup 2.x and max backups behaviour with multiple windows volumes

Server
1

We are actually testing UrBackup 2.x for backuping some branch office servers over 4/8 Mbps WAN, which works great since the 2 or 3 last betas versions.
There is just a point i’d like to underline : the max backup behaviour with Windows clients which have multiple volumes. This is our case.

We have 12 servers to backup, each with 3 volumes (C: F: and T:). To ensure the consistency of these clients image backups, we have to make sure that backup of their volumes will be made synchronously.
For now we have set the Max backups setting to 6, maximum number of simultaneous jobs per client to 3 for each client and scheduled the 12 clients on Sat/8-24
But we have noticed that some clients were having their volumes backup launch separately when a backup window becomes available.

IMHO the right chronology would be :

  • Backup window is reached
  • CLIENT1 -> start image backup > VSS snapshot of volumes C: F: and T: -> backuping the 3 volumes
  • CLIENT2 -> start image backup > VSS snapshot of volumes C: F: and T: -> backuping the 3 volumes
  • Max backups reached, waiting for 3 backups window available to launch next client
  • C: volume backup from CLIENT1 is finished , 1 backup window available
  • Waiting for 3 backup window available
  • T: volume backup from CLIENT2 is finished, 2 backup window available
  • Waiting for 3 backup window available
  • F: volume backup from CLIENT1 is finished, 3 backup window available
  • CLIENT3 -> start image backup > VSS snapshot of volumes C: F: and T: -> backuping the 3 volumes
  • etc …

Don’t know if i’m very clear, tell me if i’m wrong

Regards,

2

I guess the problem is that currently the volumes are backed up separately.

Going forward I would support volume set backups more like this:

  • Setting to define volumes which need to be backed up as a consistent set
  • Create the snapshots of the volumes as a set (Windows supports this)
  • Fail all the backups if the backup of any of the volumes fail
  • Delete the volumes as a set

Now the scheduling isn’t the problem if the volumes are all snapshotted at the same time. Then it doesn’t matter that they are not backed up simultaneously.

3

Ok so you mean that even if there is only one volume backup running, e.g CLIENT1 => volume C:, the two others (F: and T:) are nevertheless snapshoted and will be backed up from these volume snapshots ?

4

What uroni means:
Windows can take shadowcopies of any volumes you like at any given point.
So if you make shadowcopies in one turn of your drives they are consistent with each other at any given point.
what you have to take into consideration: as long as those shadow copies are active (not deleted) they will take up space. that grows more the longer you have them active…
NTFS uses COW techniques at that point…

5

Yes, i known the VSS snapshot concept …
My question was : if, for example, urbackup starts an image backup of CLIENT1 (which have 3 volumes) while there is already 5/6 backups running, it will start a 6th backup, but only for one of the three volumes, right ?
Lets say it starts an image backup of CLIENT1 C: volume, a VSS snapshot will be taken for this volume, but does F: and T: will be snapshoted at the same time or only when they’ll be backed up in their turn ?

Regards,

6

So for the moment, if i well understand, clients image backups are not consistent if the 3 volumes backup are not started simultaneously, isn’t it ?

7

Yes, it also does not guarantee that they are perfectly consistent if started simultaneously.

8

@Uroni,

Do you plan to implement this in a next release ?
IMHO it’s an important lack of the software today to be used in full “real life” production because we cannot ensure the integrity of VMs with multiple volumes, as they can be backed up separately for the moment …

Regards

9

Or maybe add a parameter “Max simultaneous client backup” :
e.g if set to “2” :


             /=> Backup of volume C:
                /
               /
CLIENT-1 <=>---=> Backup of volume F:
           \
            \
             \=> Backup of volume T:


             /=> Backup of volume C:
                /
               /
CLIENT-2 <=>---=> Backup of volume F:
           \
            \
             \=> Backup of volume T:

CLIENT-3 won’t start while CLIENT-1 or CLIENT-2 finished

10

Will be in 2.1.

11

Thank you this is a very good news :sunglasses: !