CBT not functional for one local drive

Is this a VM or a physical system?

It it is a VM, is the disk different defined as the others? Independent versus dependent…

Do you have complete error messages  or a logfile you can post here?

This is a physical system. Running a backup job gives no error but the log shows that one of the six drives doesn’t use CBT (and incremental backup on this drive needs 17 min whereas the other drives need 1-2 min). The drive in question as well as 3 others are SSD two are rotating. 

where could be a logfile located?

I uninstalled and reinstalled Veeam Agent. Didn’t help

This drive, most likely it‘s not NTFS.

We have two CBT mechanism.

• The default CBT mechanism, which works only for NTFS volumes. Veeam Agent will use the Master File Table to track changes.
• Our own CBT driver, which works also with reFS and FAT volumes.

I assume this drive is an reFS or FAT volume? If yes, then  you must install our CBT driver if you want to use CBT for this volume.

There is no option to install Veeam CBT driver

This option is available in Server Edition. Starting with Veeam Agent for Windows v6, the CBT driver is also be available for the workstation edition.

Our free edition doesn‘t include the CBT driver.

Best,

Fabian

It’s definitely NTFS. And yes it’s the free edition. 

is the restore CBT option only available for Veeam CBT?

Does it make sense to present the partition information for all the drives. 

Is this disk backed up at all?

Yes, please give the details of the disk/partitions.

oh. I’ve been on error 😥

It’s only 5 disks but 6 NTFS partitions. The partition tabel of the disk in question has two NTFS partitions:

DISKPART> lis par

  Partition ###  Typ               Größe    Offset
  -------------  ----------------  -------  -------
  Partition 1    Wiederherstellun  1996 MB  1024 KB
  Partition 2    System             400 MB  1998 MB
  Partition 3    Reserviert          16 MB  2399 MB
  Partition 4    Primär             310 GB  2415 MB
  Partition 5    Primär             618 GB   312 GB

DISKPART> lis vol

  Volume ###  Bst  Bezeichnung  DS     Typ         Größe    Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     G   SSD2         NTFS   Partition    465 GB  Fehlerfre
  Volume 1     F   3TB-WD-RED   NTFS   Partition   2794 GB  Fehlerfre
  Volume 2     D   SpeedyData   NTFS   Partition   2794 GB  Fehlerfre

  Volume 3     C   SPEED11-SYS  NTFS   Partition    310 GB  Fehlerfre  Startpar
*  Volume 4     E   Virtual-C    NTFS   Partition    618 GB  Fehlerfre

  Volume 5         Wiederherst  NTFS   Partition   1996 MB  Fehlerfre  Versteck
  Volume 6                      FAT32  Partition    400 MB  Fehlerfre  System
  Volume 7     H   SSD1         NTFS   Partition    465 GB  Fehlerfre

Volume 3 and 4 are on one disk. All volumes but Volume 4 (E: Virtual-C marked with a “*”) use CBT. See screenshot

Hello @BstAA 

To install CBT Driver:

https://helpcenter.veeam.com/docs/agentforwindows/userguide/cbt_install.html?ver=60

To reset CBT Driver:

https://helpcenter.veeam.com/docs/agentforwindows/userguide/cbt_reset.html?ver=60

@Moustafa_Hindawi 

He already told in a previous comment is using the free edition. So your solution will not work.

Best,

Fabian

Yes and “Resetting CBT” doesn’t work either, as this is only for the “Veeam CBT driver” 

So question is:

1. Where to find a solution for the Windows integrated driver? OR:
2. If uninstall / delete setups / reinstall could help: How to rescan the existing backups?

Klaus

@BstAA

I found an internal case where one of our SE had the same issue. There was an invalid MFT file record.

Solution was to run a chkdsk against the volume. This fixed the invalid MFT records for this volume.

Best,

Fabian

@Mildur 

Sorry, didn’t help in my case. My test case:

1. Setup a single volume backup job 
2. Create Full backup
3. run

   chkdsk /F E:

   on the volume (no errors reported!)
4. Create incremental backup → again no CBT usage.
5. Create 2nd incremental backup → again no CBT usage

Question: Must I run chkdsk before creating a full backup? Or what can I do?

I have to reopen this thread: Still a new problem with CBT on Windows free agent. History:

1. Full backup of the whole system with a new job
2. Incremetal backup → One drive doesn’t use CBT → slow speed
3. Reformat this drive / restore data to this drive
4. Incremental backup → automatic backup of all data of this drive marked with CBT
5. Incremental backup → now CBT again is gone 😫

Anybody any idea?

An update to this old thread.

I’ve seen this issue intermittently on one drive out of five. Workstation edition running on Windows 11 if that matters. Backups working but one 4 TB drive not using CBT so much slower than it should be.

In my case, it had nothing to do with corrupt MFT entries or other data corruption on the volume.

This volume has many VMs. Backups worked without issue until we deployed some VMs using a network appliance based on BSD. My suspicion is BSD on these VMs didn’t play nice with VSS. 

We used the network appliance VMs for a couple of months and then retired them. As soon as we removed the BSD VMs, CBT started working again.