How do I exclude one guest disk when backing up Hyper-V?

I have a Hyper-V guest that I backup using Duplicati on the Hyper-V host. The guest has one system disk that I want to backup and a secondary disk that I don’t want to backup (it’s large and contains stuff I don’t need backup of)

How can I use the exclude settings in Duplicati to acomplish this? Either exclude the whole disk or exclude everything on it, whichever is best or possible?

EDIT:
I actually have two guests that I need to do this on, one Windows 10 and one Debian Linux.

I found only one solution: to backup Hyper-V files without this disk and not a Hyper-V machine.

Same here, I only backup the VHD file I want backed up and not the complete Hyper-V machine for this particular guest machine. The others are backed up as complete Hyper-V. Both ways have worked very well so far for me.

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When backing up the raw VHD/VHDX file, is the Hyper-V VSS writer still involved? In other words, is the guest VM still “asked” to make applications consistent/quiesce the filesystem?

I would imagine the signal is sent to all VSS enabled applications, meaning any Hyper-V application active will get a flush signal.

I have not worked much with Hyper-V, but as I understand your request, you would like to back up one machine and not another? If you make a backup of the VHD, that should be sufficient, but may include more data than you want. Last I looked, this worked fine with VSS flushing the disk.

Is your question about using DPM ?

Or is it about choosing the HyperV machines via the GUI? In this case, it does not support choosing the individual disks. I do not know if it would be possible to extend the query used to list HyperV machines, to also include disk information, but it is possible.

A workaround would be to include the VHD files and make sure you have --snapshot-policy=required

@kenkendk

My post is from 2018 :slightly_smiling_face: and I’ve done it like this since then:

I backup a number of both Linux and Windows Hyper-V guests. Most of them I backup as complete Hyper-V machines in the Duplicate GUI. But the guest machines where I want to exclude backing up some secondary data disk I dont add as machines and instead only backup the vhd/vhdx I want as files (with vss snapshot set to be required). This since I didnt find a way to backup a whole machine minus an excluded disk. This has worked very nicely. The only thing I’ve noticed is that after a restore, booting a restored machine there are some errors that it wasn’t shutdown properly (which it obviously wasn’t when backed up live :grin:)

I only run one Hyper-V host so no DPM.

If you set the backup option that vss snapshot is required as @kenkendk mentions but I suspect this is only host based maybe, all types of guest system might not be aware. If any.