Using the GUI I thought it maybe possible to run the same Snapshot on multiple devices however that doesn’t seem to be the case. I can view Snapshot created on one PC on another, but they don’t update the snapshot’s repository. And there is no “Snapshot now” button.
Further I was seeing an “overdue” label on PC 1 until I viewed the snapshots on PC 2, which owns them.
So if that’s correct I assume I need to create Local Snapshots on each device? If so a real time saver would be the ability to duplicate a Snapshot from another PC to be used as the basis of a new local snapshot.
Better still would be the ability to run the same snapshot across multiple devices.
@FrankM Thanks for that, however I’m not trying to synchronize repositories. I’m trying to synchronize the same directory structure on multiple PC’s to the same repository.
I don’t think I understand what you’re trying to achieve. Do you have multiple PCs with similar data and your intention is to save on bandwidth, etc?
This generally is not needed and deduplication “just” works - each PC will compute the hash of files it encounters and will only upload to the repository if the file (more precisely content) with computed ID does not exist. Because identical files will have identical hashes regardless of machine, you will not have any data stored more than once (there are some minor race conditions when you’re snapshotting exactly the same new data on multiple machines, but over time compaction will remove redundant copy).
Here’s a test you can run:
Snapshot a large directory on PC1.
Measure size of the repository (kopia content stats)
Copy directory to PC2
Snapshot the same data on PC2
Measure size of the repository again (kopia content stats) - the size difference should be negligible.
This also works if you change the file modification time, rename it, etc. In most cases if you have a very large file and you make a small change to it, deduplication will avoid having second copy - it will just copy the difference using dynamic boundaries computed using rolling hash algorithm.
Jarek, thanks for replying and apologies for not be clearer in my use case.
I’m a solo software developer and I switch between a Desktop PC and Laptop PC to work on the same code at different times. I sync the two PCs using a Windows Backup/Sync app.
In addition I want to backup each of these PCs to a Synology NAS and to Cloud Storage.
When I’m working on code on the Desktop it backs up using Kopia. Then I’ll sync these changes to the Laptop and continue working on the same code base there, which I want backed up to the same Kopia repositories.
So it isn’t about saving bandwidth, its all about having a set of Kopia repositories which always have the same files as whichever PC I’m currently working on.
Is there a problem with independent backups of two PCs? You will get two sets of snapshot manifests, but the underlying files will be exactly the same and stored once. To restore, you can always pick the latest snapshot from either PC and restore to whichever one you prefer.
I assume independent backups work fine. I’m in the process for setting up a new laptop and will confirm and reply.
That said, getting back to my opening post, what would be great in this scenario is the ability to use the same snapshots across multiple PC’s. A snapshot can take a while to configure and maintain. So having to create and maintain identical duplicates is a bit of a chore.