4948 platform recommendations

Unanswered Question
Jun 29th, 2007

To save space and reduce the amount of cabling in our data center, we are considering a migration to top of cabinet distribution layer for our servers.

Each cabinet houses 16 servers. Currently the servers are dual-homed on copper to a pair of 6509's, and also have ILO capability (16x3=48)

1) Reliability - I have seen only one field notice (corrected) for the 4900's. Are they solid? Anyone have experience with them?

2) Dual-homing the server Nic's (NFT Mode). Any brilliant ideas for doing this without using a pair of switches per cabinet?

Thank you, Mike.

I have this problem too.
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We just built out our new data center and used the 4948's for server aggregation. They are solid, dependable and fast switches. We are currently using 12 of them.

We designed the switches to use 10G, Layer 3 uplinks to a dual core setup. The cores are 6509's with single sup 720's each.

We run the 4948's in an HSRP pair between two cabinets. Each server has dual NICs, with one NIC attached to one switch, and the other NIC to the other switch. The 4948's have a 10 gig link between them and a 10 gig uplink to one of the cores. This will result is a highly fault tolerant server aggregation layer. Any single device or link from the server to the core can fail, and you will not lose connectivity.

I do not see a creative way, even with redundant power supplies, to make a single switch any more fault tolerant. If that switch fails, then you are down.

You can look at using 2 switches to serve 4 cabinets (assuming 12 servers per rack). There will be some long patch cables from servers to switch, but in practice these will be less than 50 feet. I would recomend using a lesser switch for ILO (say a 2950 or what ever you have on hand - we use 3550-EMIs). This will off load the port count to a lower capacity and speed switch. Think of the vlaue of a 4948 port compared to the value of a 3550 port. Roughly 1/4 the cost per port.

Our business is 24/7/365. Each hour of down time can cost us from 100K to 500K in lost revenues, blown SLAs, product spoilage, trucker delays, overtime, etc, etc, etc. It's expensive not to be able to move Cherrios! So when you try to sell this type of fault tolerance to a business, you gotta ask what's it worth. I can buy 4948-10G's for about 12K each. Cheap insurance if you ask me...

Hope you find this helpful.

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