I've implemented Nimble at my enterprise in the last few months. My environment consists of around 20 VMware hosts (Dell PowerEdge R720s) running ESXi 5.1U2. They are connected to a Cisco Nexus 7000 core via 10 GbE SFPs.
One of the things I've run into is poor copy performance when running Server 2012 R2.
I've been testing using the same ~2 GB file (database backup). If I run the copy from Server 2008 R2, I get consistent copy speeds of 100+ MB/s. The same copy on Server 2012 R2 gets stuck at 20-25 MB/s, bouncing up and down, and sometimes dropping to 0 b/s and pausing for some time.
I've done quite a bit of research on the issue, and have tried the following solutions:
1 - Disabling SMB digital signing - this gives a slight performance bump, but only to about 40 MB/s.
2 - Turning of Receive Side Scaling (RSS) - same as #1
3 - Updating Server 2012 with all hotfixes - no change
4 - Disabling Chimney, offloading, etc on guest (VM) server Nics.
5 - Disabling Symantec Endpoint Protection - this gives about 10 MB/s increase - but still not enough to bridge the gap between 2008/2012.
I've involved Microsoft, as I've seen some postings about possible bugs in SMB 3.02 in Server 2012, but they want me to get rid of all Nimble software connections and use Microsoft initiators, which defeats the purpose of Nimble Connection Manager on servers.
Has anyone experienced a similar issue? Just wanted to float this out on forums - I'll most likely be contacting Nimble Support in the near future as well.