Re: Image Catalog over NFS

Hello Bryan,

thanks for chiming in.


Am 21.10.2024 um 23:45 schrieb Bryan Dietz <bdietz400@xxxxxxxxx>:

in V7.5 NFS defaults to TCP according to the memo to users.
since you are at still at 7.3, I doubt you could add "tcp" to the end of the "options" parm.

Well, this is for an OS based mount, which I'm not talking about. I'm talking about NFS based remote image catalogs. This is completely independent of the IBM TCP/IP stack. You can only configure a leftover (otherwise unconfigured) virtual Ethernet adapter in an LPAR and assign an IP address via SST. The result is the Service Tools Adapter. No NFS options configurable whatsoever. And according to the documentation, NFS over UDP is — was? — the only available option.

https://www.ibm.com/support/pages/ibm-i-save-and-restore-using-virtual-optical-images-nfs-server — this page is from 2022.

I admit that my scenario — with the NFS server using jumbo frames (to speed up transfers for other, also jumbo enabled clients) but the NFS client for remote image catalogs is not — is probably rather special. But it's a possible pitfall, hence I've pointed it out. I "pitfell" twice! ;-)

In addition, I rarely observed the need to fiddle with NFS options on Linux after around 2000. Automatic parameter optimization seems to work for many disparate operating systems and different client/server implementations nowadays. Including IBM i.

Finally, I'm not appalled to using UDP for NFS in virtually lossless, high bandwidth LAN environments. 20 bytes more payload per packet because of no TCP header for free? No expensive TCP checksum computing? I'll take it! :-)

:wq! PoC