Adding a new switch to my EVA, will this work?

[Kevin Everts_1]

I have an EVA 3000 with two Brocade 8 port SAN switches. My switches are full and instead of buy two new switches, I want hoping I could just buy one. I'm looking at buying an HP Cisco MDS9124 16-port switch. Would this work with my existing switch? Is it possible to daisy chain my two existing brocades together so that I will have 15 usable ports?

[TTr]

If I understand you correctly you want to put in a new 16port switch as half of your fabric and thw two old 8port switches as the other half.

You can daisy chain the 2 8port switches to make them act as one but,

1. you have to create an ISL trunk which will use at leat one port on each switch. You will have performance issues if you only use only one port on each switch, you would use 2 or more ports on each 8port switch for the ISL. This would reduce the number of available ports to 6 or less, total (12 or less).

2. The ISL requires a licesne which is expensive

It is better therefore to buy two switches instead of one.

[Bill Costigan]

You would have 14 usable ports not 15 because you'll lose 1 port on each switch.

The ISL might not cost you anything depending on what product number you bought to get the brocades. Some of the HP brocade part numbers included a license for 2 switches other part numbers included licenses for 4 switchs and some for 0 switches. You'll need to check the license on both switches and make sure they both incluse some fabic license.

I'm also assuming you are goign to connect the two brocades together and and you are not planning to connect the Cisco to either Brocade. mixing vendors in that same fabric is tricky.

Lastly, I would try to design the 2 switch fabric so that very little traffic went across the ISL. Connect one EVA controller to switch#1 and the other to switch#2. configure the hosts connected the switch#1 to access EVA controller#1. Same for switch#2 and controller#2. All the hosts will see both controllers so it would be easy to have a configuration where half of all your traffic is trying to squeeze through a single ISL.

[TTr]

Bill's suggestion is a very good one too depending on what you have to pay for the ISL license and whether a one port ISL would be sufficient. It all depends how many busy servers you have.

If I may suggest an alternative to connecting the two 8port switches to the EVA.

Depending on how many busy (I/O) servers you have and your zoning, you can connect both EVA controllers on one 8-port switch and put all your busy servers on this same switch. Then you put your less busy servers on the other 8-port switch where they have to cross the ISL.

[Bill Costigan]

A third option if you don't have the ISL licenses and don't want to buy any.

Connect a port from each EVA controller to the Cisco and then connect one of the two remaining controller ports to Brocade #1 and the other to Brocade #2.

Now you have 3 separate fabrics. Connecting a server to the Cisco and to one of the Brocades will give you 3 paths to the EVA instead of the full 4 paths.

You'll still have alternate paths and can load balance while saving some money.