Guys I would like to ask how do you all design networks for sql server deployments I would also like to hear the reasoning on why you designed it the way you did? I'm getting ready to implement some database mirroring using sql server 2008. So I was thinking to have the network guys set up vlan for sql server than set up link aggregation. I also thought about having 2 nics for regular traffic than 2 nics for sql server traffic but I guess if I use link aggregation it's pointless to use two vlans one for regular traffic and the other for sql data based traffic. Anyway can you guys pleas let me know what you do at your various shops
I usually setup pretty much everything redundant. You can setup a dedicated VLAN if you'd like, but a large amount of traffic will be coming to the SQL Server, so that may just put extra load on the switches CPU for no reason.
Any NIC that you have there should be two of. Bridge them together in Windows. This will make Windows use them as a single NIC. Nothing special needs to be done to the switch to make this work. This way if one NIC stops working (or the cable is cut or the port dies, etc) the other NIC will handle the traffic. Best practice states that you would have each NIC connected to a separate network switch.
You can run the mirroring traffic over a separate private network, but most of the time this is overkill. The Network link isn't going to be the bottleneck, the disks will be long before the network is.
It depends what you want to achieve. We did this for a large bank's loyalty programme:
2 x Web front-end with Network Load Balancing on a DMZ
2 x SQL Server 2005 (clustered) inside the LAN, but that can also be in its own segment in its own DMZ.
1 x App server, in the same network segment as SQL, which does one fast pipe into the SQL cluster. Since the web is slower than SQL every time, there was no need to have two NICs into SQL (except for redundancy).
Hope that helps!