What to look for in a datacentre ethernet switch

datacenterhardwarenetworking

This is a Canonical Question about choosing a network switch for a datacentre

When shopping for a networking switch that's going to be going into the top of a datacentre rack, what specific things should I be looking for?

i.e. What makes a $3,000 Cisco switch that requires annual maintenance a smarter buy than a $300 Netgear Smart switch with a lifetime warranty?

Best Answer

Context is everything... There's no blanket answer.

If you're trying to ask: "what differentiates an expensive switch from a low-end switch?" or
"is there a reliability difference between a high-end switch and an inexpensive switch?"

The answers are "feature-set" and "maybe", respectively... I've used a $40,000 switch for the specific purpose of connecting two 10GbE WAN connections in a data center cabinet. I've also seen $100 unmanaged Netgear FS524 switches run the "core" of a $400 million/year company for 9 years, with no reliability issues...

"You're only using me for my 10GbE ports, routing capabilities and good looks..." - Cisco 4900M. enter image description here

If you're looking for a rule or general advice that can be applied across the board, there are more questions that deserve attention:

  • What type(s) of systems are co-located in the data center facility? - This is basic. Running a pair of web servers at a cheap colo is different than managing a full application stack or virtualization cluster in a high-end facility.
  • What is the purpose of the switch? - As above, if there are throughput, latency, buffer or other performance considerations, that's going to drive the type of equipment you use. And there are definitely switch attributes that impact the success of deployments for iSCSI, VoIP, PoE, low-latency and streaming technologies.
  • What interconnects are required? - These days, this may determine the class and tier of switch more than anything else. People want 10GbE connectivity for storage and other network workloads. Below a certain price threshold, you simply won't find that type of connectivity. Fiber? SFP+? Compatible with Copper DAC? Dedicated stacking links? HDMI?!?
  • How complex is the network? - Will these switches link back to a core? Are they the core? What's their place in the overall design? In my work environment, we use lower-end Layer-2 access switches that offload the heavy lifting to a central core switching/routing infrastructure.
  • Power - Depending on the colo/facility, power constraints, etc., redundant power supplies are a nice option. But they're not a requirement. I rarely see switch power supplies fail. But it's possible to keep a cold-spare and copies of configurations handy, too. Redundant power supplies often push devices into a much higher price bracket.
  • Cooling - Fan design, hot-pluggability and the option to control switch airflow are nice features.
  • What resiliency and redundancy options do you need? - Chassis switches, modular switches, stacked switches and standalone devices can all have different levels of resiliency. But I think their feature sets and other network design considerations tend to be more important.
  • Warranty and support - I don't buy Cisco SmartNet often enough... But the product is so ubiquitous that finding technical resources/parts/support hasn't been difficult. I think the HP ProCurve Lifetime Warranty is often overlooked. For something like Netgear, I don't know that they would provide good technical support. As stated earlier, if the cost is low enough to afford cold-spare units, you can self-support on the hardware side.
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