Restic with rclone and upload when big file changed

Hello,
i’m using a restic script with rclone to backup my notebook (win 11 pro)

i have this question, if i have a big file (1GB outlook pst)
first time i backup it , of course , i upload 1GB.

but when i open outlook and download or modifiy pst with 10MB , restic upload all 1GB or only “delta” 10MB?

thank you

If the modifications to the PST file is not spread out all over the file, the delta plus some more will be transferred. Not the entire file.

i don’t know how outlook write PST but i think write small chuck of file.
so big thank you :slight_smile:

i hope also virtualbox write vdi in same way, because i would backup my VM… :grin:

thank you again

I use KVM, and after using a 300GB Windows qcow image I typically have an extra 20 GB added to the next snapshot.

big thank you

happy to hear that :slight_smile:

And how does restic behave if a file changes during its backup? I have a KVM with a qcow2 disk image, can I back it up with restic without turning off the VM?

i don’t know how restic works on linux.
if windows host i think windows create a snapshot with running VM…

If a file is change while restic reads it then the backup contains a mix of old and new data. To get a consistent snapshot you’ll have to use LVM snapshots or those provided by the individual file systems.

The same behavior applies by default for Windows. Although there’s the --use-fs-snapshot option to let restic create a snapshot before backup.

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