Drobo

A probably silly question about rsync server.

Hi everyone,

I have a question about the DroboApp rsync server and I was curious if anyone could enlighten me.

Specifically, what’s the advantage of running the rsync server on the Drobo as opposed to just initiating the rsync command from the computer side?

With my old Drobo, I had a cron set up to run “rsync -avp --delete /source/ /target/” - what’s the point of the rsync server?

Thanks for any input you folks can provide,

Steven

rsync can be used to sync local to local or local to remote. So if you were syncing to a USB drive, it would be local to local. If you were trying to rsync to a remote file system that is mounted locally using Samba or NFS on a Drobo FS, then you are dependent of those protocols to access the remote files. If you run rsync server on the remote server, rysync will connect directly using TCP (port 873 by default) which allows the remote rysnc process to access the remote file system directly making the overall sync process more efficient.

The other option with rsync to/from a remote location is to run it over another transport, most commonly SSH (the rsync option is --rsh=“ssh”). This has a few advantages in general:

  • SSH is secure, so everything on the wire is encrypted, even the login
  • you only need to port-forward or open a single port on your router and you can use straight SSH, rsync over SSH, VNC over SSH, etc.
  • If you have passwords set up for SSH, you don’t need any other password files
  • You can even set up SSH to use pre-authorized keys (public key/private key) so you don’t need passwords, but only you can get in
  • Using things like FUSE you can “mount” drives over SSH onto a remote computer desktop just like you would with Windows or Mac file sharing

As you can tell, I’m a BIG SSH fan. Once you get to grips with it, it’s probably the single most important tool in your tolbox if you have to access anything remotely.

I just bought a Drobo FS. I’ve tried to read and understand the DroboApps, but I don’t find much in the way of documentation to clue me in. If I wanted to use 2 Drobo FS’s, one storing work data, and the other at home with music, movies, etc. Is there a way that each Drobo could back itself up to the other Drobo, thereby being each other’s offsite backup? Which apps would you use? Any help is greatly appreciated.

If you mount up a network share using Samba/CIFS or NFS and use rsync then what happens is rsync treats all files as local. This means that if a file has changed it copies the whole file from the source to the destination.

If you run rsync and connect to a a server or to a remote machine via ssh then rsync uses the rsync algorithm which only transfers parts of files that have changed.
This makes it far more efficient for transferring updates to medium or larger files.

For rsync as a server vs rsync over ssh, rsync as a server will be faster transferring over the network as it does not have the overheads of encryption. Also it will transfer faster as the limited CPU power of the DroboShare/DroboFS won’t waste cycles encrypting/decrypting ssh data.
On the flip side its obviously unencrypted - so fine over a LAN but probably not what you want over an insecure network like the Internet.

Thanks, AJ. That explanation tells me everything I need to know. I’m doing this within a local network and inside a firewall, so I’m not worried about the encryption, but if running the server reduces overhead and makes the whole process less process intensive, that’s all to the good.

Thanks!