I've moved on to CommVault for our VM backup's, but we too are still seeing what I think is a similar issue. We saw the issue in Veeam on ESXi v5.5 and it followed with CV on ESXi v6. I opened a case with VMware and this is the KB they returned.https://kb.vmware.com/selfservice/micro ... Id=1022543
Ultimately I think its a memory leak on their side, but that's tough to prove considering they couldn't tell me how to monitor the memory consumed, or even see the number of connections supposedly opened. As you can see the KB has existed since 2014, so it doesn't look like its anything that VMware is too concerned about. I realize the KB is just telling you what will happen when you hit the limit and ultimately doesn't tell you how to resolve the issue (other than restarting the management services), but perhaps if enough folks open a case and link to this KB, we can get some traction in VMware. It does however tell you where to look in the logs to see if you're in fact hitting the limit, so that might be of use too. Also, I realize the KB doesn't list ESXi or vCenter 6, but the VMware support person told me its still applicable. Finally, they of course blamed it on the backup vendor for leaving orphaned connections, hard to believe both CV *and* Veeam are doing this, but maybe its possible.
Hope that helps.
BTW, I don't recall if Veeam does this, but it would be helpful to throttle NFC connections per host and per vCenter in total, otherwise you'll hit this in the best of conditions. The limits for each are outlined here, and each disk counts as a unique connection. http://pubs.vmware.com/vsphere-50/index ... _4_0_2_3_1
Limits You To About
to an ESX host
9 connections directly, 27 connections through vCenter Server
to an ESXi host
11 connections directly, 23 connections through vCenter Server
to an ESXi host
Limited by a transfer buffer for all NFC connections, enforced by the host; the sum of all NFC connection buffers to an ESXi host cannot exceed 32MB.
52 connections through vCenter Server, including the above per-host limit.