OpenFiler performance tuning best practice for iSCSI Windows file server use

I don't believe the ReadyNAS 2100 supports cluster (ie multiple concurrent host) access to iSCSI targets. This in not uncommon on entry level iSCSI h/w. That may be fixed in a firmware revision, best ask NETGEAR directly.

I would think hard about using sync. I'm reminded about the Dirty Harry 'Do you feel lucky' speech.

NFS v2 and v3 is designed such that when the write is acked from the server to the client the data is on disk. This allows NFS to be stateless, and, therefore, the server COULD reboot between each request. One hopes not, but it could happen.

This means that if the client sees the ACK on the write then it doesn't have to care anymore about the data being on disk.

If you use async then this is not true anymore. It will be way faster though. Basically though if you use async, and, the server crashes, you probably should reboot the clients unless you know exactly what they do since if they are expecting to keep multiple files in sync the client may believe they are in sync, when, in fact, they are not.