conf-sanity, test_76a fails every time on any el7 client as far as I can tell. This test attempts to prove permanent param changes made with 'lctl set_param -P'. This mechanism doesn't seem to work at all when the client is el7.
I can manually reproduce the problem by mounting a lustre filesystem, observe the 'max_dirty_mb' param on the client with 'lctl get_param osc.*.max_dirty_mb' on the client, then manually alter that param on the mgs by manually exectuting 'lctl set_param -P osc.*.max_dirty_mb=64' from the command line on the mgs. If I have the lustre filesystem mounted on both an el6 and an el7 client I can see the change from 32 (the default) up to 64 in the results of get_param cmd on the el6 client after a few seconds. The value is never seen to change on the el7 client at all. It appears to stay at the default value of 32 forever, never visibly changing.
The fact that the change can be observed on an el6 client indicates the change on the mgs is really happening and is eventually reaching the el6 client, but somehow it is never reflected back into the el7 client.
There must be some significant difference on el7 causing the failure there, but I'm at a loss to explain it. I think I need a higher level expert to help with this problem. Without some solution I don't think we will get a 100% test run on an el7 client ever.