CT creation on nfs storage really slow

I saw a thread about this from a few years back but it didn't go anywhere.

I have 2 nodes in cluster and they are connected to an nfs share via Infiniband to a ZFS storage server.

I used iperf to confirm thruput to around 4gb so the link is fine.

But when I create a new container and choose to store the private area on the NFS share, the creation takes forever.

I go to the ZFS server and watch the folder grow by about a mb per second.

Is this just the unpacking and rsyncing over the wire taking forever? Tiny files dont do good on any network link i know.