Server-side compress before backup?

[Rarst]

I am using Cobian Backup for weekly automated backup of images, plugins, etc via FTP. This ends up being a lot of files and fetching them one by one has considerable overhead.

So I wonder about improving that, but don't exactly know how to tackle issue.

Basically I need archive with stuff to backup either served in response to Cobian request or ready by the time Cobian starts to fetch it. Naturally having archive with most of stuff publicly available is bad idea so has to be secured as well.

So what do I do? Use WP-cron and PHP Zip to schedule compression of folders into some directory, not accessible from web?

I brushed through Zip stuff in PHP docs and it seems like trouble with file-by-file iteration and memory issues.

Any ideas or available solutions appreciated. :)

[Rarst]

If anyone needs it I managed to do it with WinSCP via SFTP/SSH.