I have a local Linux server that I'm using to backup two remote Windows 7 boxes over an IPsec VPN tunnel connection. I have the user's Documents folders shared on the remote PC's and have mounted those shares (CIFS) on my local Linux server.
I'm going to use a cron job to run rsync on my local Linux server to create backups of these folders and am currently considering the -avz args to accomplish this.
My question is this: does the -z arg do anything for me since the mount is to a remote machine? As I understand it, -z compresses the data before sending it which definitely makes sense if the job were being run from the remote PC but, it seems like I'm compressing data that's already been pulled through the network given my setup (which seems like it would increase the backup time by adding an unnecessary step).
What are your thoughts? Should I use -z given my setup?
Thanks!
It won't save you anything. To compress the file, rsync needs to read it's contents (in blocks) and then compress them. Since reading the blocks is going to happen over the wire, pre-compression, you save no bandwidth and gain a bit of overhead from the compression itself.