| Hi Anna-
As usual, you pose some interesting questions for us.
You can always use "setenv DISPLAY" to detach the user interface
from the system where it is installed. This incurs the overhead
of X over the net, and doesn't distribute much of the processing.
But it is an option. Other than that, you need DMS.
We have tested DECmcc in a DMS environment, but not extensively.
Both the server and client systems require DECmcc licenses (see the SPD).
> - since, in a diskless env. it will be necessary to do writes across
> the network, I think that using PrestoServe will also be needed or we
> will take a significant performance hit?
Nothing really specific to DECmcc here. If you use DMS, you incur some
network overhead. Prestoserve improves disk I/O throughput at the server.
If you have a local swap partition on the client, then the network
I/O may not be as bad as you think (although dictionary performance
may be a problem). We have not taken any performance measurements
in the DMS environment.
> - The server (DECsystem) disk are being shadowed, using Digital's
Sorry, we have no experience at all in this area. Why would DECmcc
present issues related to shadowing? I thought shadowing was supposed
to be completely transparent to applications.
> - Can anyone advise me (pros and cons) as to WHY I would want to
> convince the powers that be to change the configuration (even stating
> the obvious)? I have my own ideas but would like to see if someone with
> more experience with DECmcc can back them up (please).
Well, we generally stay away from DMS here because of the performance
implications. The Ethernet is busy enough with VMS LAVC, NFS, and
general network traffic without DMS in addition.
In a production environment, I would question adding an additional
network dependency to a product that may be used for network management.
I would pose the opposite question: Why do you want to use DMS?
Unless you have a number of stations wishing to run in the same configuration
(or are REALLY tight on disk space) DMS is not an obvious choice.
Shadowing, on the surface, seems like a good idea (to protect against
disk failures). I don't know about performance implications.
-- Erik
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