Thanks.
The primary NAS has 2 x 1TB drives in RAID 1 config.
The backup NAS has 1 x 1Tb drive and 1 x 750Gb drive in a JBOD configuration.
Both nas boxes are currently plugged into the same gigabit network switch and I'm attempting to backup just over 600gig. The network also consists of a Fortigate gateway and dual wans. One is an ADSL line with a generic provider supplied router, the second is a D-link 4G router. The two NAS drives have the Fortigate as their default gateway, but the internal to internal rules are any allow.
Primary nas has Volume1, then under that several shares, for example "Shared Data", "iTunes Library", "Photos" "Videos" etc.
The backup nas just has Volume1 with no shares other than the Volume1 share.
The NAS to NAS backup source is set to the primary Volume1 level. This way it will backup all my shares. The destination is set to Voulme1 on the backup NAS. The options are set to not encrypted and ignore existing files is set.
The primary see's the backup fine, and does actually back up to it, but it never finishes all the files. The first time I ran the backup, it copied one root folder and all it's contents, then stopped. The second time it copied 3 root folders and their contents. I ran it again and it started copying the 4th root folder. Some times it doesn't appear to copy anything new, other times it seems to copy loads. I'm not convinced every directory it does appear to have backed up contains all the files. The backup nas holds nothing other than the backup from the primary and shows 252Gb used, so well short of where it's supposed to be.
Each time I run the backup it seems to spend a very long time not doing anything that I can see. When it stops it just goes back to Ready with no errors or indication on what was/was not done.