How to use mounted FTP as backup location

How is the FTP location mounted? If you're using a FUSE driver so the FTP site looks like a regular mount point, my guess is probably yes, though we've not tested this and can't guarantee performance and expected behavior.

In addition, consider hardLinkLocal option to create a full- or object-level backup with hard file links on a local database host.
One of the advantages is that it uses significantly less disk space than a backup with copies of database data files.
However it cannot protect you from file system or node failures because data and backups are on the same nodes.
See: https://www.vertica.com/docs/9.3.x/HTML/Content/Authoring/AdministratorsGuide/BackupRestore/CreatingHardLinkLocalBackups.htm

@mosheg Thank you for your response. Indeed, I sync the backup folder to an external S3 like storage. So the backup is maintained elsewhere for node failures. I will explore the hardLinkLocal option. Would that be useful if I take a full backup with the hardLinkLocal option and sync this folder externally for node failure situations?

Hard link is fast and save disk space because it create two file names that both point to the same physical location on a hard disk.
However, when transferring hard-link local backups to other storage media it copies the data files associated with the hard file links,
which will consume the same space on the target media as the original source files.
Transferring Backups to and from Remote Storage is described here:
https://www.vertica.com/docs/9.3.x/HTML/Content/Authoring/AdministratorsGuide/BackupRestore/RestoringHardLinkLocalBackups.htm

@mosheg Thanks for your response. Your suggestions looks like something I could try. However, I did not see any reduction in disk space after setting the hardLinkLocal = True in the [Transmission] section of the .ini file. Some thing I 'm doing wrong or have missed?

For hardlink to work properly the backup folder must be on the same partition as the data folder.