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Sending savesets over TCP/IP to Linux.

Posted: Sun Jul 02, 2023 1:04 pm
by martin
My backup scripts consist of a master script running on the main server and a small slave on each VM or remote machine. The master calls up the slave via SSH and directs stderr to the log and stdout to the dumpfile. The slave MUST send ONLY the dump over stdout, all other reporting is done over stderr.

Integrating a VMS VM into this! I've hit two problems:
  • I can't find a way to cleanly link SYS$OUTPUT to stdout and SYS$ERROR to stderr, and then ensure that ONLY the saveset flows over SYS$OUTPUT/stdout.
  • Alternatively, I've tried running the BACKUP command through OpenSSH, but specifying a remote file for the saveset won't work. I know it's easy with DECnet (done it often enough in the past) but I'd like to do it over TCP/IP/OpenSSH.
Latest (failing) attempt:

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$ BACKUP /IMAGE /RECORD /COMMENT='gemini-dka100' dka100: "<FQDN>:/tmp/bups-gemini-dka100-rkMXUm"/save_set
Where <FQDN> is of course the host's name.

Any suggestions/pointer please?

Re: Sending savesets over TCP/IP to Linux.

Posted: Mon Jul 03, 2023 5:14 am
by hb
martin wrote:
Mon Jul 03, 2023 4:02 am
At last some useful information. Are you stating that BACKUP cannot use TCP/IP in the output filespec? It can use DECnet (along the lines of BIGVAX::DISK$BACKUPS:[BACKUPS]GEMINI.BCK)...
A DECnet node is part of a VMS file specification. A TCP/IP node is not, except for a few commands, which accept the FTP qualifier - as far as I know only COPY, DELETE and DIRECTORY.
... but with only (currently) one VMS VM hosted by Linux then DECnet isn't an option. If BACKUP can't use TCP/IP, then there is no point in pursuing this development, which is where we came in.
There was and probably still is DECnet for Linux - although there was some discussion in last August to drop support for it. Some distributions don't configure it in the kernel. So you may not have it by default. And you need the dnprogs. This is old code and probably not well maintained. So DECnet may not be an option.

Re: Sending savesets over TCP/IP to Linux.

Posted: Mon Jul 03, 2023 12:11 pm
by martin
There's not much point in continuing this discussion, others have provided constructive help which shows that I need to approach the problem in a differrent way. I thank them.
"running the BACKUP command through OpenSSH" or "specifying a remote file".
OpenSSH enables you both to log into remote machines, and also to run commands on the remote machines:

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$ ssh gemini "dir DISK$USERS:[JMR]"

Directory DISK$USERS:[JMR]


Total of 1 file.
for example. Here a user logged into a *NIX box is running a VMS command ion a VMS machine using OpenSSH. OpenSSH establishes contact in the normal way, then sends the the remote machine "gemini" to be executed there. It's really quite straightforward but is unfortunately not documented in VSI TCP/IP Services for OpenVMS User's Guide V6.0. If you have access to a UNIX or Linux machine the man page will explain it.

Some commands, such as the "r" or "s" commands allow you to specify that the source or destination is a file on another emachine. This is called "specifying a remote file". Its converse, specifying a local file, would mean that the file was on the actual machine executing the command. Using DECnet this has been possible since the early days, and when clusters were introduced the issue was clouded slightly since the definition of "remote" was a bit elastic. With two networking systems now used by VMS it would be nice if either could be used, but apparently not.

Re: Sending savesets over TCP/IP to Linux.

Posted: Mon Jul 03, 2023 2:24 pm
by marty.stu
Closing this thread as the OP got their answer and to prevent further offtopic.