01-08-2013 09:48 AM
I have a two node VMS cluster running OpenVMS 8.3. These two nodes run a X11 graphical program many people here need to access. Clients are mostly using Xming (or hummingbird) on Windows.
Traditionally people have logged in via telnet, set their DISPLAY variable and then run the program. This is however quite fragile as IP addresses can change and the telnet service on the VMS boxes seems to stop working rather frequently.
So I started experimenting with using SSH and SSH X forwarding to handle this for me, and as an added bonus get rid of plain text passwords and other data flowing thru the LAN here.
Both Xming and Hummingbird know how to use either putty.exe or plink.exe so the setup and config was easy. However once the app is running I see almost a 10 fold increase in latency when using the program. Flipping pages in the app was quite responsive when X was connecting directly but becomes very sluggish via SSH.
I tested logging in to a Linux machine that is in the same server room as the VMS cluster with putty and X11 forwarding and running apps on them and they did not show any slowness over SSH, compared to direct X11 connections.
So I need to figure out why SSH connections to OpenVMS 8.3 are so slow. It does remind me of a very old problem I had with HP-UX back in the day when HP-UX did not have a decent /dev/random device and SSH was starved for decent entropy for encryption purposes, but I have no way to know if this is the case on VMS as I'm really not that good with VMS.
Any help would be appreciated.
Thanks in advance,
01-09-2013 05:27 AM
>> I have a two node VMS cluster running OpenVMS 8.3. [...]
> Not much meat on that bone. About what kind of hardware are we
> talking? AlphaStation 200/100? Some fancy multi-GHz-CPU server?
> Memory? Quotas?
> Not a very complete problem description.
> What investigation have you done? Is the CPU (are all the CPUs)
> busy while this stuff is running? Memory? Page-fault rate? For a
> The description of this hardware is no more useful than the earlier
> one of the VMS hardware. I would not be amazed if a modern,
> resource-rich x86 system were faster than some decade-old, resource-poor
> Alpha system. But, with my weak psychic powers, I know approximately
> nothing about your hardware (or the users' resource quotas, or anything
> else, really).
01-09-2013 10:10 AM
Process Entry Slots 356 292 62 2
Balance Set Slots 354 292 60 2
The portion of the SHO MEM above indicates to me that you are running a bit short on memory. As indicated by Steven, get more memory for this system. That should make a tremendous difference overall.