In any case, we high recommend you build two or more servers for load balance, that will bring you more reliable.  From SANDeploy 3.0, it support multiple server load balance and Windows XP, Windows 7 failover (multi-pathing).

For per server requires:

Clients count <50

• CPU: Intel Core i3, Core I5, Xeon 3000+, or AM3 Processor 2GHZ - 3.0GHZ
• Motherboard: Intel / AMD Compatible
• RAM: 4GB DDR2
• Hard Disk: At least 2 Hard disk, 1 for system disk, 1 for client data disk.
• Network: GB Ethernet
• System: 32 or 64 Bit

50 < Clients count <100

• CPU: Intel Core i5-i7,or AM3/AM3+ Processor 2GHZ - 3.0GHZ
• Motherboard: Intel / AMD Compatible
• RAM: 4-8GB DDR3
• Hard Disk: 3-4 Hard disks. 1, for system disk, 2 for client data disk, build Raid0 or Raid5 (3 data disks)
• Network: GB Ethernet * 2, build trunk is recommended.
• System: 64 Bit

100 < Clients count <250

• CPU: Intel Xeon 5000 Series x2. Opteron 6000 Series x2.
• Motherboard: Intel / AMD Compatible
• RAM: 8GB DDR3 Hard Disk: 3-4 Hard disks. 1, for system disk, 2 for client data disk, build Raid0 or Raid5 (3 data disks)
• Network: GB Ethernet * 2, build trunk is recommended.
• System: 64 Bit