I need LAGs. Lots of LAGs!

They greatly improve performance and system uptime, which is generally a good thing:


Each Server has uplink through two independent gigabit Ethernet connections to two stacked Network Switches, while the SAN unit connects via four gigabit links.This is implemented by configuring two port Link Aggregation Groups (LAG)  for each server across the SummitStack. The server NICs are teamed up in vmWare.


Connection to the sister stack is made by means of long range fiber. There are four lambdas reserved on a sizable WDM backbone ring, each carrying a gigabit link across the country and abroad, interconnecting the two stacks at a fully redundant 2gbps. Any one link between each component of the system will fail gracefully.


Entry Level Cloud on a Budget


The Hardware

The Hardware for our cloud project:

– 4x Extreme Networks Summit X440 Switches
– 8x DELL PowerEdge 2950 Twin Quadcore Servers (refurbished)
– 2x Promise VessRAID 1840i+ iSCSI SAN
– 32x 2TB Seagate SATA HD (7200rpm)
– 16x 120GB Kingston SATA SSD

I got the 8 PowerEdges off of eBay, for about half the price of a single, all-new-all-shiny top-notch-state-of-the-art machine. They came equipped with twin quadcore XEONs @ 2.33GHz, 32GB RAM and a PERC 5 integrated RAID controller.

The VessRAID I chose because it had some pretty decent reviews and promised (no pun intended) quite some bang for the buck, especially when compared to other solutions. A big plus are the 4 GigE ports, as I will make heavy use of link aggregation (LAG) in this project. It’s much easier to handle a bunch of LAGs in a stack than it is to handle the same bunch of MLAGs across two switches… Not implying that I ain’t gonna put MLAG to use though!

The Extreme Networks Summit X440 offer 24 GigE ports (4 shared copper/SFP) and can be stacked quite easily. Also, the company has broad, existing knowledge of ExtremeXOS and because the X440 is rather affordable. Plus I think they’re pretty nifty, too!