I have my Unraid server (A) doing frequent Duplicacy backups. The initial backup is complete.
I want to incrementally copy that backup over to computer B via SFTP.
I tried to follow the docs about the copy command but have no idea where to even begin. I need some examples.
Can someone please help? What do I need to do on Computer B? All I have done so far I have installed the duplicacy CLI installed.
Assuming:
your A backs up to server B1
You want to replicate that backup to SFTP server B2.
If you use WebUI – configure both storages, and then add Copy task to schedule.
Since you spoke about unraid and zfs in another topic — if your duplicacy storage resides on a separate dataset — another option is to replicate entire dataset with zfs send/zfs receive. It’s fast, incremental, sequential, and is a filesystem feature, no extra software required.
Thanks for assisting again. Much appreciated.
Not quite. I want Computer A to backup to an internal disk. Then I want to wake computer B and pull that backup from computer A to a local disk on computer B. I only have two computers. So I only want to backup my backup to computer B.
What would these commands look like? I am completely lost.
How do I point the storage to another computer?
I think I will need some genneric examples.
am going to assume I failed explain coherently so I am going to try again, sorry.
Basically I am trying to mitigate the risk of a ransomware attack by pulling a Duplicacy backup to a second computer with an external drive over sftp.
Here is the gist
What I don’t understand is how to actually technically do this in Duplicacy.
I really hope someone can help as I have just bought a second computer primarily for this task.
For the curious: Why pull-based backup?
At first glance this may seem weird — like, why not just setup an FTP server on Computer B and let Computer A upload to it?
Say for example that Computer A is is hacked. If computer A has write permission on Computer B then the hacker can completely destroy all data including all snapshots on computer A and B. Whereas if Computer B only has read-access on computer A, the attacker can only destroy computer A, but computer B has the backup.
Not weird at all - this is how I do it. 
Forgive me if I don’t provide the exact commands, but the gist is pretty much the same order as @saspus described. i.e. init, add, then copy.
On Computer B, you need to init to Computer A’s storage through sftp. (Initialisation doesn’t just mean setting up a new storage; when the storage already exists, it’s now referenced for use as a backup/restore/copy destination/source.)
Also on Computer B, add a new local (for B) storage, by copying the storage name (-copy storageA). (If you didn’t specify the storage name in the init step, it’ll be called “default”, so I suggest giving it a proper name in that step, i.e. storageA.)
Lastly - again on Computer B - run your copy command on your chosen schedule.
(Computer A isn’t doing anything except operating as an sftp server, so it’s Computer B doing all the work in this pull configuration.)
Thanks for helping out. Much appreciated!
Sorry, but I am still super confused 🫨
Can you try to be more specific when you walk me through the steps? I am probably the idiot here, but I get very lost with relative words without specific context (this/that). I am still new to all this.
The repository and backup on Computer A is already complete so I assume I won’t have to do anything more on that computer.
The first thing I did on Computer B was:
I cd into the repository folder where I want the .duplicacy file (not the actual data). In this case:
cd C:\data\config\duplicacy\nova_appdata_duplicacy_backup
Then I initialize the ftp storage with:
duplicacy init -e nova_appdata_duplicacy_backup sftp://username@192.168.10.10:2022/nova_appdata_backup
it prompts for the ssh and storage password — good. Then it says:
C:\data\config\duplicacy\nova_appdata_duplicacy_backup will be backed up to sftp://username@192.168.10.10:2022/nova_appdata_backup with id nova_appdata_duplicacy_backup
Then it generates the `.duplicacy/preferences which looks like this:
[
{
"name": "default",
"id": "nova_appdata_duplicacy_backup",
"repository": "",
"storage": "sftp://username@192.168.10.10:2022/nova_appdata_backup",
"encrypted": true,
"no_backup": false,
"no_restore": false,
"no_save_password": false,
"nobackup_file": "",
"keys": null,
"filters": "",
"exclude_by_attribute": false
}
]
Is that correct?
Note: The IP and username is just a redacted version not my real one.
Then, I guess I should proceed with the add command but I really don’t understand how to use it. I have tried for hours, but I am so lost. I tried:
duplicacy add -copy default default2 nova_appdata_duplicacy_backup Q:\nova_appdata_duplicacy_backup
…but I have no idea what I am doing at this point. Sorry, I don’t have a degree in computer science 
Correct. Note that the id in this case is really just a dummy - it won’t actually be used to backup, and doesn’t need to reference an existing ID. (Normally I use something like dummy but it doesn’t really matter.)
Did that not work? It looks correct, what errors did you get?
Remember, the id is just a dummy. You may need to make them unique, though. So dummy for the remote and dummy2 for local. Give it a try. Once the add command completes successfully, take a look at the preferences file and you’ll get a better understanding.
(You can directly edit the preferences file rather than re-run the commands. Maybe a good opportunity to rename the storages from default/default2 to something better.)
How can I make Duplicacy read from the root directory of an SFTP storage?
If I use:
[
{
"name": "default",
"id": "nova_appdata_duplicacy_backup",
"repository": "",
"storage": "sftp://username@192.168.10.10:2022/",
"encrypted": true,
"no_backup": false,
"no_restore": false,
"no_save_password": false,
"nobackup_file": "",
"keys": null,
"filters": "",
"exclude_by_attribute": false
}
]
I get:
Source storage set to sftp://username@192.168.10.10:2022/
The SFTP storage directory can't be empty
Removing the trailing forward slash doesn’t make a difference.
I have double checked that this path works in FileZilla with the same credentials so I know Duplicacy should be able to read the files without any permission issues. Here is the evidence:
Double slashes should do it:
sftp://username@192.168.10.10:2022//
Thanks. Where did you get that info?
I tried "storage": "sftp://username@192.168.10.10:2022//", but got:
runtime error: index out of range [-1].