Change block tracking FAQ

Some questions might also be answered by reading the user manual.

Is the licensing per client or per server?

It’s per client, so you will need one license per client.

If I install change block tracking on one client, will automatic updates remove the change block tracking when it updates to a new version?

It won’t update clients with change block tracking if the servers is setup to download and distribute a client without change block tracking.

Does the purchase include updates?

Yes, the purchase includes 2.x updates, that is fixes and updates are free after initial purchase.

Can I automatically install change block tracking on all my clients?

After purchase you will receive instructions on how to configure your sever such that it distributes a client with change block tracking. You will need to purchase a change block tracking license for each of your Windows clients or disable change block tracking on clients for which you have not purchased a license.

How is the licensing enforced? Is there a license server? Does it need a internet connection?

At this time licensing is not enforced, there is no license server and it does not need a internet connection. This is done with the hope that you will not illegally use change block tracking without having purchased a license. It may become clear that the license needs enforcement via software, in which case a license server will be supplied.

How does the change block tracking affect performance?

In non-crash persistent mode it has only negligible effects on performance. In crash persistent mode it halves random write performance in the worst case, with the worst case being a disk with long seek times (spinning disk), random writes and only new sectors being written. The performance hit is less, but proportional to the performance hit of having an active snapshot with snapshot storage on the same disk.

What is the road map with respect to change block tracking?

In order of priority

• Use CBT information for image restore (special restore CD), such that the restore is as fast as an incremental image backup with CBT (incremental restore) if the volume is restored to the original volume
• Add incremental restore support for VeraCrypt and BitLocker encrypted volumes to the special restore CD

How can the client be open source and change block tracking be commercial?

The change block tracking driver is a separate work from the UrBackup client, resides in the Windows NT kernel and is used via the Win32 ABI. For your benefit the UrBackup client is still licensed as AGPLv3+, that means you can for example change and recompile the UrBackup client and freely distribute the result. See the GPL FAQ for further details.