New switch. Nexus 3048 or Catalyst 3850/4948E

[emrinaldo]

We are looking to refresh our core switch in our DC.  I'm partial to the Nexus but don't want to break the bank.  Our environment is huge by no means.  30-40 servers.  A handful of clustered SQL/web servers.  Currently we have a 3750x that just seems to be slowing down the more we grow.  Setting up a SPAN port for our IDS system hasn't been very kind to it either.  I've been comparing the 4948E and the Nexus 3048.  Our main concern is the web traffic as we host thousands of user connections a day.  I'm looking for something with larger buffers as we have had to fight issues with microbursts with our 3750x.  The 17.5 MB of buffering on the 4948E is very appealing.  I have also had a few recommendations from other colleagues to go with the Nexus.  But not so sure management will like the pricetag.  

[Joseph W. Doherty · Accepted solution]

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Yes the 3750X has a problem with microbursts.  Unsure the 3850 is much better.  (BTW, 3750X buffers issues can be sometimes mitigated by disabling QoS, or if QoS is enable, careful buffer tuning.  Also the 3750X's uplink ports have more buffer resources than the "ordinary" edge ports.  So, your uplink ports should be used for ports having the biggest buffer drop issues.)

The 4900 series have traditionally worked well in datacenters (predating the Nexus series).  The Nexus series, though, instead of being a pizza box version of a 4500, are an architeture more designed for datacenters.  I suspect either would work well, for you, from a performance aspect.  What you may want to do is very carefully compare features and determine if any Nexus features justify its additional expense.