Here is a breakdown of the environment:
80 hosts with ESX4 and ESXi 4.1 in 30 clusters all in 1 vCenter. Hosts will be migrated to ESXi 4.1 soon
Some clusters are located in remote locations connected by WAN links
Approx 850 VMs. Windows/Linux mix
Combined used space is about 50 TB
Storage is FC SAN and iSCSI. Storage is shared between hosts within same cluster for the most part.
Traditional agent-based backup is used to backup the VMs nightly. Since this is managed by a different group so I don’t foresee it going away even after Veeam is deployed.
My preliminary design looks like this:
Veeam servers will be hybrid using both physical and VMs- -
2 Veeam physical servers for the 2 largest clusters using Direct SAN mode.
Veeam servers deployed in VMs using Virtual Appliance mode for the smaller clusters such as the ones in remote locations
Use Veeam to backup OS drives only. Data drives will be backed up using the traditional backup agent. ( I know I’m not taking advantage of all the cool features, but it’s kind of a political thing)

Questions:
I do like the ease of using a VM for the Veeam server, but I’m seeing faster backup speed using SAN mode on a physical. Is this what you guys are seeing?
Does it put more stress on the storage array when using the virtual appliance mode with the disk mounts/dismounts?
This is probably an “it depends” question, but what’s the typical dedupe/compressed ratio?
Will the restore of a whole VM be transactionally inconsistent because it’s backed up by two different tools? I’m not concerned about Active Directory or any databases restores because other 3rd party recovery tool is used.
I appreicate any thoughts/comments on this!