Pve6.4 backup to pbs2.0 has been full backup problem？

[lingguchong]

There is no incremental option when configuring the backup task. I observed the time and log of each task executed by the VM, and found that the daily backup time is basically the same as the first backup. There are writes in the log that are repeatedly used but the transmission time is still based on all The size is calculated. I hope that only the incremental part can be transferred during backup. Does this require special configuration?
The following is the task log of the same vm backup on the 27th and 28th.

 

[dietmar]

I hope that only the incremental part can be transferred during backup.

It is already doing that (reused 171 GB, so only 9GB transferred)

 

[Dunuin]

A incremental backup only needs to send changed blocks so it only transfers the 9GB of your 180GB. But there are two cases where the backup still takes forever.
1.) you are using LXCs and not VMs
2.) you are backing up that VMs with "stop" mode or your VM got shutdown between two backups
In both cases PBS can't use dirty pages so it needs to read the complete 180GB so see if any data changed. If your VM runs 24/7 without any shutdowns PBS will use dirty pages which will log which parts of that virtual disk have been written to so PBS can skip reading the parts where nothing changed and your incremental backups will be way faster.

 

[lingguchong]

I am using VM without LXC, and the system runs 7*24. In addition, I’m not too clear on the second point you said. Is it convenient to explain it?

 

[Dunuin]

When you do a backup you will be asked which mode to use. There is "stop", "snapshot" and "suspend". "Stop" is the most secure, but it will shutdown the VM for a short moment so the dirty page tracking resets. Not sure about suspend, but with snapshot your VM will continue running so BPS can make use of the dirty pages.

 

[lingguchong]

When you do a backup you will be asked which mode to use. There is "stop", "snapshot" and "suspend". "Stop" is the most secure, but it will shutdown the VM for a short moment so the dirty page tracking resets. Not sure about suspend, but with snapshot your VM will continue running so BPS can make use of the dirty pages.

After upgrading PVE6 to 7, now you can choose to stop, suspend and snapshot in the backup options. I will observe it for a few days. Thank you for your help.

 

[Dunuin]

After upgrading PVE6 to 7, now you can choose to stop, suspend and snapshot in the backup options. I will observe it for a few days. Thank you for your help.

That isn't a new features. You already needed to choose the mode with PVE6.