[c-nsp] switch for SAN

Michael Malitsky malitsky at netabn.com
Fri Jan 8 13:00:43 EST 2016

Biggest issue is buffer space.  3750X has 2750KB shared between 24 GE ports.  Switch models starting with 29XX are similar or worse.  3650 and 3850 show 12MB shared between 48 ports (http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3650-series-switches/qa_c67-729531.html).
I believe the memory allocation mechanism is also significantly improved on the 3650/3850, but don't have the links handy to support this.

We've been using 3650s to support EMC VNXe SANs, very successfully so far.  
Also used them to terminate Metro-E connections.  No problems, as opposed to the predecessors, 3550 and 3560G, which racked up output drops due to lack of buffers.  
Check your expected bandwidth needs, and the number of 10G ports.  3650 is likely to be a good fit.

4948E shows 17.5MB of memory shared between 48 ports.  I believe it is a 4500 Sup6-E in a fixed chassis with 48 ports, so fairly old by now.  That said, I have Sup6 in production supporting SAN and Metro-E with no problems.


-----Original Message-----
From: cisco-nsp [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Adam Greene
Sent: Friday, January 08, 2016 9:44 AM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] switch for SAN

Hi all,

 I know running Catalyst switches for SAN backbone fabric is not the best idea, due to limited buffers. 
However, we have been doing just that with a 3750X and Dell Equallogic 6100/4100s for quite some time, with no issues.
We are putting in a NetApp FAS3160 and need to add a switch. I see 3750X is EOL and Cisco positions the 3850 as its replacement. 3850 is even slightly less expensive than 3750X.

-          Should we expect the 3850 to perform as well or better than the 3750X for this application?
-          Is there any other switch we should be looking at which is not humongously more expensive? Maybe Nexus 3k could work, but it's a lot more expensive. Maybe 4948E? Seems up there price-wise, too . 



More information about the cisco-nsp mailing list