Hi, when downloading via FTP for backing up, restoring or migrating my site from the cloud servers, is it necessary to download the '.SVN' folder ? and/or the '_files/cache' folder ? are there any other folders not needed for backups, restore or migrating ?
You can skip downloading these two. They are not necessary. As for the rest I think all are required. But if it is just for daily or weekly backup, you are OK just downloading the _files folder and NO other folders. Because only in the _files folder the contents generated by your users is kept, and all the rest you can download from our website or we can always send you again etc.
I think the svn folders just used for back ups by admin on the cloud server. I have moved my site to a VPS server and I found that adding the existing cache files does make the new install work better