Switch inter-connectivity question

Question

Good day to all.  We have a small LAN with less than 10 switches total.  Including all the network printers and PCs and servers there are about 70 nodes in this building.  In the data room, there are (6) 24-port Catalyst switches.  I am trying to determine the best way to inter-connect them.  2 of the switches are c3750x and are stacked.  2 are C3560X and cannot be stacked, and the other 2 are C2960G and cannot be stacked.  Also, there is a C2960G in another building connected to one of these 6 via a 1G uplink.  I wish I had gotten more of the switches with stack capability, but at the time I was not aware of the advantages of stacking.
So... The 2 C3560X switches each have a 10-G network module installed.  One of the 2 3750X's (the stack master, call it Switch-A), in the stack has a 10G module as well.  In a perfect world, I would take the C3560X (the one that is layer-3 with routing enabled and also the default gateway), and connect all the other switches to that one, and use both the 10-gigabit uplinks and then use 1-G uplinks for the rest.  But if I use the 10-G ports, then I cannot use the other 2 1G SFP ports in the network module.  So I am limited to 2 10-G uplinks per C3560 switch.  I can't connect all the other switches to this one unless I used some of the standard (non-SFP) ports.
So here is the way I have it set up right now: there is a 1-G fiber uplink from another building and the fiber is FDDI so it is not possible to use a 10-G uplink between the buildings; they are too far apart for FDDI.  We might run some OM3 fiber later, but for now, the 1-G uplink is the best we can do.  So the 2 buildings are connected using a gigabit fiber uplink with SFP ports, and the fiber coming from the other building is connected to the C3560 that is not the default gateway.  The default gateway switch, call it switch-1, is using both the 10-G uplinks and has one 10-G port connected to the master in the 2-switch stack, (one of the C3750X's, call it Switch-A).  The other 10-G uplink goes to the other C3560X, call it Switch-2 (Switch-2 is the one with the fiber uplink from the other building).  Switch B is the stack slave and is only connected via the stack cables.  The other 2 switches are C2960G-24TC-L and one is connected to Switch-A with a 1-G copper SFP uplink, call it Switch-3, and Switch3 is connected to the other C2960G with a 1-G copper uplink.  I have attached a basic diagram.
So... my question is, without spending more money, is this the best way to connect them?  I could use more of a hub and spoke topology if I did not stick to SFP ports for all the up-linking.  It was my understanding that the SFP ports are the best ones to use for uplinks.  But due to the limitations of the network modules, I could not connect more than 2 SFP uplinks from a given switch, or 3 in some cases where only 1G uplinks were used.
If we did not mind spending a few more thousand (I would love to run OM3 between the buildings and get the speed up to 10G), so if we had another 5 to $10,000 to spend, would it be worth getting a switch full of fast SFP modules and using it to uplink all the other switches (a total of 5 counting the link from the other building and not counting Switch-B since it connects via the stack)?  Everything is working well, so it might be better to leave it alone.  Any helpful comments and/or suggestions are welcomed with a heaping helping of sincere appreciation!
Thanks!
Flux

Answer 1

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What you might consider is using your dual 3750X stack as the physical core and as the L3 router.  All your other switches (except the off-site switch) would have dual port channel links, one link to each 3750X.  This provides core and L3 redundancy and can provide more inter switch bandwidth.
For you critical single home devices, such as your Internet and off-site switch connections, you can have a logical configuration "mirror" port ready on the second 3750X stack member, so if the member with the active link fails, you only need to repatch.  (This can also be use for other critical single homed servers).
On a 3560X/3750X switches you do want to use the SFP ports for your busy ports (because they have their own reserved hardware buffers).  However, if you use 10g port, as 10g, you lose half your SFP ports.  Without knowing your expected traffic flow patterns, I cannot not say whether using all the SFP ports for dual gig port-channels would be better than having some on copper edge ports and some as dual 10g fiber ports.