It is mostly safe to backup a Windows/MacOS box to a Linux host, but you need to consider the following factors:
- for data (ie: file content), there is not problem
- for ACL metadata, you need to copy files using an utility capable of not only read/write ACLs, but also to store them in EXT4 format
- regarding the Windows box, if alternate data stream are present and they need to be copied as well, you are out of luck, as EXT4 (nor any other Linux filesystem, for what I know) does not support them
All considered, I am extremely satisfied using rsync + rsnapshot combo. Using them, you can schedule automated, deduplicated (via hardlinks) backups. Using the right options (-AX
), rsync is even capable of storing ACLs. For the MacOS box, you will find native rsync support. For the Windows box, you can install it via Cygwin