On 2021-08-17 14:26, Justin Parisi wrote:

NFSv4.1 performance is nearly identical to v3 in ONTAP for sequential reads/writes. The performance issues mostly come from high metadata workloads. If you do want to use v4.1, move to ONTAP 9.9.1 and the latest Linux kernels you can.

Yes. And therein lies the problem. Anything which has many files (high inode density), many open() and close() operations and lots of deletes of [small] files will suffer significantly (higher processing util in WAFL and extra latency) from using v4.1

The current performance penalties in v4.1 w.r.t. ONTAP compared to v3, are not easy to fix. Maybe something can be done inside ONTAP to mitigate but it's never going to "go away" easily to become on par overall with v3 performance any day soon. Metadata ops (esp GETATTRv3) is very very optimised in ONTAP in v3, for example

I agree 100%: use 9.1.1 (latest stable Px whatever it is) and make sure that you have the latest Linux [kernel] version(s) you possibly can. It will help. (One of the very latest is highly preferable.) If you want to get proper enterprise level support, then use the latest RHEL 8.x, keep it well patched all the time, and you'll at least lower the risk if having issues.

If you have a specific application system(s), e.g. one which really depends on v4.1 ACLs (I have yet to hear about such an animal that isn't esoteric) or some other feature v3 doesn't have (there aren't many IMO) then you can probably "contain", and hence control that environment much better including the involved NFS clients. If not... caveat emptor.

/M