I have now done the installation and taken the first backup.
This is what I ended up doing.
Installed B&R on the physical Windows server and attached the NAS directly to a free NIC port on the server using iSCSI.
Installed the Proxy on a virtual Windows 8 workstation.
So the disks of the virtual machines gets hot added to the proxy and then the data is sent over the network to the physical Windows server who stores it on the NAS. Then the data is copied from the NAS to the directly attached tape library. Nothing too complicated.
I have two B2D jobs and two subsequent D2T jobs.
The first B2D job is a Incremental job that runs every day with synthetic fulls once a week with the option to transform previous full backup chains into rollbacks. Active full backups are run three times a year. I have chosen to keep 365 restore points at the moment. I have a tape job as secondary job.
The second B2D runs a full backup once a year and then writes that backup to tape for archiving purposes.
The two B2D jobs write to different repositories on the same disk.
In total there's 11 virtual machines backed up, 2,3TB data totally. The NAS holds 11TB. The tape media pool for daily backups holds 11 LTO4 tapes and the archive pool holds 9 LTO4 tapes. I have three free slots that I can assign as needed. The daily backup pool is set to get overwritten as needed, I guess I have to watch out so that the full backup doesn't get overwritten before a new full backup gets done?
What I noticed is that the first full backup took a very long time. Processing those 11 machines with 2,3TB took over 65 hours. The incremental backup the next day was fast.
The full backup started out at over 80 MB/s but as it progressed it kept dropping constantly and in the end it was only 5 MB/s resulting in an average of 23 MB/s. These are the bottlenecks: Source 7% > Proxy 26% > Network 21% > Target 88%.
The feeling I got is that the B&R server isn't powerful enough. It's a HP ProLiant DL380 G5 with two dual core CPU's at 2GHz and 16GB memory (memory shouldn't be the issue). Looking at the task manager the first CPU core is at about 80% and the other three at 50% during backups. The process VeeamAgent.exe is the the one taking most of the power at about 25%, does those 25% mean something like maxing out one core?
The backup server also have vCenter on it and the SQL databases for both vCenter and Veeam.
Should I have a more powerful machine as backup server?
Also, depending on your hardware, it might be possible to use Direct SAN transport mode with SAS storage, please look at this topic
This was not an option since the backup server is in another location. I have read that the first Optical SAS products have appeared but we're not there yet.