Operating System - OpenVMS

NFS server on OpenVMS slow performance

Jan Andersson_3
Occasional Advisor

NFS server on OpenVMS slow performance

I have installed NFS but get bad performance.

Copy 5MB from NFS Server (OpenVMS) to NFS Client (Linux)

real 0m19.284s

Copy 5MB from NFS Client to NFS Server

real 0m2.193s

Doing the same with ftp:

ftp> get
5483813 bytes received in 0.69 seconds (7.8e+03 Kbytes/s)

ftp> put
5483813 bytes sent in 0.67 seconds (8e+03 Kbytes/s)

Putting the nodenames in each local hosttable did not improve.

Tried another VMS-server with the same result.

First server is OpenVMS 8.3 and FTP V5.6 - ECO 3
Second server is OpenVMS 7.3-2 and FTP V5.4 - ECO 4
Linux client is Redhat

Mount command: mount -t nfs -o hard,intr,rsize=32768,wsize=32768

Mounting with default 8196 gives four times longer transfers, so it is very linear.

Occassionally I have had the same speed on NFS as on FTP, but only on the first attempt. The consequent attempts were slow.
Now it is permanently slow.

I don't think this is a tuning issue while copying one 5 Mb file.

Linux node is on the same lan but in a different domain.

Setting up another Linux node as NFS-server shows no speed problem (but it is in the same domain as the other Linux node).

Any ideas?

Regards /Jan
Honored Contributor

Re: NFS server on OpenVMS slow performance

This does look to be a lower-level or NFS Server (or NFS client-level) issue.

Start ruling out cases and triggers, and do use extreme caution around statements such as "I don't think this is a tuning issue while copying one 5 Mb file" without supporting evidence. (That statement is a _huge_ red flag, BTW. My experience with those statements leads me to go look right at whatever was ruled out, too.)

This rule-in/rule-out troubleshooting sequence certainly includes measuring any differences with the inter-domain routing that's mentioned here; a problem with that can nuke performance. Look at the network window sizes and MTU settings, too. At the NFS Server settings. Look at the gigabit (if you're using it) settings, too. Look at the speeds of the NICs and the LAN and the duplex settings. Look at the error counters (via LANCP) for the NIC(s), as well.

Also have a look at the TCP/IP Services Management manual section on tuning nfs, and at the TCP/IP Services Troubleshooting and Tuning Manual. The former has more detail here, while the latter has general detail.

And some questions that probably should be prolog: what disk and what OpenVMS server hardware, and what are the basics of the NIC and network configuration here? This configuration does look like it's running pretty well for an OpenVMS NFS Server connection with a Linux NFS client, all things considered.

This question is also cross-posted posted to comp.os.vms.


and there are some other options discussed out there.
Jan Andersson_3
Occasional Advisor

Re: NFS server on OpenVMS slow performance

I made a case of this to HP.
My assumption:
"I don't think this is a tuning issue while copying one 5 Mb file"
was right. It has nothing to do with tuning or hardware setup.
Hp finds no cause and points at engineering.
NFS on VMS has performance issues.
Case is closed.