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Cisco Nexus 1000v limitation getting more apparent

With the advent of high capacity machines (1TB RAM, 4×10 CPU)  – consolidation ratio is at its all time high.

Unfortunately, maximum/ limitation of other components would easily be reached.

One good example: we recently experienced VM’s suddenly disconnecting -NICs getting unchecked- from Nexus1000v. We verified there were a lot of free ports left on the 1000v.

After hours of troubleshooting, we finally found the culprit and its stated on the public document:

http://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus1000/sw/4_2_1_s_v_2_2_1/Resource_Availability/Reference/n1000v_resource_availability_reference.html#wp43988

Nexus 1000v has a limitation of  300 vEthernet interfaces per host.

This means if you have 150 VMs sitting on one host with 2xNICs each- you’ll start to experience the same problem. This number starts to go down the more you add virtual NICs to the VM. 😕

How to verify if you are exhausting this number:
 show resource-availability vethports

…so yeah. just a word of advice to anyone using high capacity hosts and running Cisco nexus 1000v.

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