Both the choice of drive size (146GB vs. 300GB) and the number of drives (10 vs. 15) was for cost considerations. We were not able to put the money in for anything larger at the time. I don't need that much storage for these VMs anyway.
One server that is not virtualized is the main file server, it is still on a physical machine. This was done for two reasons: 1) It's datastore is very large - approaching 12 TB. VMware cannot handle this as a VMDK, it would have to be a RDM, and I'm not sure even then if > 2TB is supported. 2) The storage for this is on a 3rd party iSCSI SAN that is not certified for use with VMware.
For backup, I have a 4th server (other than the 3 in the VMware cluster) which is a physical machine that is the network monitor, tape backup, vCenter, and a few other items that require physical hardware that isn't supported by VMs. I'm running Symantec Backup Exec on that machine, it backs up all servers including all VMs to tape. This is an older version of Symantec Backup Exec (v 11d), which does not support VCB, so I have deployed the Backup Exec Agent inside all the VMs.
That is the primary backup solution. Since Backup Exec doesn't do a bare-metal restore real well (I have the IDR option, but I've used it for recovery a few times and have not been happy with the resulting restored machine), I have a secondary backup solution where I have deployed Acronis True Image Echo Server for Windows inside each VM. This does an image backup of the VM's C drive only once a week, saving the image on the physical file server (the 12 TB server I referenced above). Those images in turn make it to tape via Backup Exec.
That's a total of 5 physical servers -- the 3 VMware ESXi machines, 1 physical file server, 1 physical vCenter/Backup server. All are Dell PowerEdge 1950s.
I have looked at replacing the Acronis secondary backup with VMware's Disaster Recovery (DR) option, as that is included with the Essentials Plus package that I bought, but so many people are reporting problems with DR that I have decided not to deploy it at this time.
Be aware that making Backup Exec's remote agent and Acronis True Image co-exist on the same server is painful. You MUST install the Backup Exec Remote Agent first, then install Acronis on top of that. If you ever need to update the Backup Exec Remote Agent, you must remove Acronis, update the BE remote agent, and then reinstall Acronis. Doing it any other way will result in blue screen crashes during a Backup Exec backup.
Backup performance is quite good, Acronis can image a server with a 16GB C drive in approximately 5-10 minutes. Backup Exec's performance is highly dependent on the server it's running on and the specific tape drive you're using. The physical server running Backup Exec is a 2x Xeon 5310 (2 cores per Xeon), with 8 GB of RAM running Windows Server 2003 R2 x64. The tape drive is an HP MSL 2024, a 24-slot autoloader with a single LTO-4 drive. I can get up to 2GB/minute (~35 MB/sec) with this setup, this is primarily limited by the 3rd-party iSCSI SAN. If the storage was on the MD3000i it could be double that.
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