How to sync "symbolic links" in linux?

[CRD]

Hi there!

I've just installed FFS and it seems really great. However, I'm trying to sync two linux machines and I cannot find, for my life, a way to sync symbolic links (which I want to be identical in both machines). I always get the error message "Operation not supported between different devices."

I've ticked "Direct" in "Include symbolic links" in the Synchronizing Settings.

Can someone, please, advice? Many thanks!

[Zenju]

What is the full error message?

[CRD]

Hi Zenju,

The full message is:


Cannot copy symbolic link "sftp://server/folder/link" to "/folder/link".

Operation not supported between different devices.



Any ideas?

[CRD]

More details, in case it helps: I'm using FreeFileSync 11.1 on Linux Mint 20 Cinnamon...

[Zenju]

FreeFileSync should support this. => ToDo

[CRD]

Thank you , Zenju!

Just for reference, in case some one else is in the same situation, I'm syncing the symbolic links in the meanwhile using rsync:

rsync -avzu -e ssh "remotehost:/path/remotesymlink" "/path/localsynmlink"

(see rsync man page for details...)

[ryoushi86]

Hello,

Any update about this issue? I'm trying to copy symbolic links between 2 devices and the error message is :
Info : Creating symbolic link "/mnt/whatever"
Error : Cannot copy symbolink link
"sftp://mnt/whatever to /mnt/whatever".
Operation not supported between different devices.

I'm using FreeFileSync 11.5 on Debian 10 with "Direct" box ticked

Thank you for your wonderfull software !

[mdrmdr]

I second this request to be able to sync symbolic links from (in my case) Linux to Windows. A Linux symbolic link should result at Windows in the file the link is pointing to.

Thanks a lot!

[Zenju]

I second this request to be able to sync symbolic links from (in my case) Linux to Windows. A Linux symbolic link should result at Windows in the file the link is pointing to.

This should already work. See "Symbolic Link Handling": https://freefilesync.org/manual.php?topic=comparison-settings

[mdrmdr]

Unfortunately not. I get "Operation not supported between different devices." I included symbolic links as "direct". I use FFS 11.5 on Windows and access Linux via ftp.

[Zenju]

Unfortunately not. I get "Operation not supported between different devices." I included symbolic links as "direct".

So this is also SFTP => Windows?

[mdrmdr]

Not SFTP, standard FTP.

[Zenju]

You need to set symlink handling to "follow".

[mdrmdr]

No success. Then I get many errors like

CURLE_FTP_COULDNT_RETR_FILE: RETR response: 550
550 '/opt/automation/config_links/000-default-ssl.conf' is not a directory [curl_easy_perform]


[ryoushi86]

Syncing symbolic links between 2 linux boxes would be very nice :)

[mdrmdr]

FileZilla also shows the 550 error:

Command: CWD 000-default-le-ssl.conf
Answer: 550 000-default-le-ssl.conf: Not a directory


But then it does not stop and just copies the linked file....

[Zenju]

FileZilla also shows the 550 error:

Command: CWD 000-default-le-ssl.conf
Answer: 550 000-default-le-ssl.conf: Not a directory


But then it does not stop and just copies the linked file....

Indeed. The FTP protocol is very limited compared to SFTP regarding symlinks but FreeFileSync might be able to do something about this => ToDo

[mdrmdr]

:-)

[Zenju]

The FTP protocol is very limited compared to SFTP regarding symlinks but FreeFileSync might be able to do something about this => ToDo

Implemented! FreeFileSync now handles symbolic links pointing to files via FTP (before it only supported links pointing to directories)
https://www.mediafire.com/file/o9m2m2y0c61al7w/FreeFileSync_11.6_%255BBeta%255D_Windows_Setup%25284%2529.exe

[mdrmdr]

Installed 11.6 Beta and still the same error "Operation not supported between different devices". German error message attached.

[Zenju]

You still need to set symlink handling to "follow".

[mdrmdr]

If I set it to "follow", I get this error for each linked file:

[mdrmdr]

In the affected directory on my Raspberry, I have links to files and directories. I'd like to only sync the linked files, not the directories. Excluding the directories still gives the above error.

Actually I would expect the following behaviour:
• "direct": sync linked files and ignore linked directories
• "follow": sync the whole tree of a linked directory (possibly with a "depth" parameter?) and sync linked files

Therefore I'd prefer "direct" with the above behaviour or "follow" with "depth=0"

[Zenju]

If I set it to "follow", I get this error for each linked file:

It seems "fullchain.pem" is incorrectly considered a directory. Here's a debug version of FreeFileSync, which error details do you get?
https://www.mediafire.com/file/t7mj94453u3zbs5/FreeFileSync_11.6_%255BBeta%255D_Windows_Setup%25285%2529.exe

[mdrmdr]

Same "is not a directory" error during "compare" as before for any linked file with "follow". No further details. Where should I see more details?

[Zenju]

Did you run the same test case? I've added code if the item name is "fullchain.pem" and FreeFileSync will show a different error message. Also check you're really running the correct beta and not some other version.

[mdrmdr]

Now, the only link to be synced is:
cert -> /etc/letsencrypt/live/dyn.xxx.de/ (link)

Within "/etc/letsencrypt/live/dyn.xxx.de/":
fullchain.pem -> ../../archive/dyn.xxx.de/fullchain450.pem (file)

This gives:

FFS3.jpg (43.07 KiB) Viewed 3659 times

If (for debugging only):
cert -> fullchain.pem (file)

it works and FFS syncs the the path "cert -> fullchain.pem"
So it seems that FFS only is able to follow 1 level?

if (for debugging only):
fullchain.pem -> /etc/letsencrypt/live/dyn.xxx.de/fullchain.pem (file)
I get:

FFS4.jpg (31.54 KiB) Viewed 3659 times

[mdrmdr]

Upate: Now the attachments of the above post are correct...
--
(There seems to be an attachment inlining problem at your board. The second picture after "I get" should be
FFS4 not FFS3 again...)

[mdrmdr]

But again: My standard case is to follow links down just by one level to exactly one file. If a link points to a directory, the danger under Linux is, that a huge tree is affected. Therefore I'd exclude links to directories and only let FFS sync links which directly points to a file. For the above debugging example, I had to move some files out of "/etc/letsencrypt/live/dyn.xxx.de" so that FFS only finds "fullchain.pem".

[Zenju]

Now, the only link to be synced is:
cert -> /etc/letsencrypt/live/dyn.xxx.de/ (link)

Within "/etc/letsencrypt/live/dyn.xxx.de/":
fullchain.pem -> ../../archive/dyn.xxx.de/fullchain450.pem (file)

This gives: [SIZE: 550]

This is either:
1. an issue with the FTP server: it cannot find the file at /opt/automation/config_links/cert/fullchain.pem although it should, or...
2. /opt/automation/config_links/cert/fullchain.pem is a broken symlink

If (for debugging only):
cert -> fullchain.pem (file)

it works and FFS syncs the the path "cert -> fullchain.pem"
So it seems that FFS only is able to follow 1 level?

This is FFS's new file-symlink support => okay

if (for debugging only):
fullchain.pem -> /etc/letsencrypt/live/dyn.xxx.de/fullchain.pem (file)
I get: [SIZE: 213]

This is also FFS's new file-symlink support => okay
(the error message only comes up because it is the debug version)