NFS vs SMb vs iSCSI for remote backup mounts

Hi,

I would like to get some input from people who have used these options for mounting a remote server to a local server. Basically, I need to replicate / backup data from one server to another, but over the internet (i.e. insecure channels)

Currently we have been mounting an SMB share over SSH, but it's got it's own set of problems. And I don't know if this is optimal, or if I could setup something better. We don't have much control over the remote server, so I couldn't setup a VPN, or iSCSI or anything else. My options was FTP & SMB.

But I want to move the backups in-house, to save bandwidth and have more control over what we do.

So, with a new CentOS server & 2x1TB HDD's in RAID1 configuration, I can do pretty much whatever I want. The backup server(s) will serve backups for multiple servers, in different data centers (possible in different counties as well, I still need to think about this), so my biggest concern is security.

We mainly use cPanel & DotNetPanel (Windows ServerS) , but also WebMin & VirtualMin, so I need to stick with their native backup procedures and don't really want to use a too technical backup system.

The end users need access to the data 24/7, so having the remote share permanently mounted seems to be the best for this, then our support staff don't need to SSH into the servers and download the backups. With the mount, I can also use rsync backups, so an end user could restore only a single file if need be.



NOW, the question is: Which protocol would be best for this? I can only think of SMB, NFS & iSCSI
The SMB mounts have worked well so far, but it's not as safe, and once the SMB share is mounted, I can't unmount it until the server reboots. This isn't necessarily a bad thing, but sometime the backup script will mount the share again (I think this is a bug in cPanel) and we end up with 4 or 5 open connection to the remote server.

NFS - last time I looked at it was on V3, which was IMO rather slow & insecure.

iSCSI - this doesn't allow for more than one connect to the same share. Sometimes I user might want to download a backup directly from the backup server via FTP / SSH / a web interface, which I don't think will work. We also sometimes need to restore a backup on a different server (if for example the HDD on the initial server is too full), so this isn't possible.

The remote shares also need to be mounted inside XEN domU's, or directly on CentOS / Windows servers.


what would be my best option for this?

 

Doesn't anyone use SMB, NFS or iSCSI?