[Info-vax] VMS to VMS data copy options/performance when losing a DECnet link

[Bob Gezelter]

On Thursday, April 7, 2022 at 7:24:03 PM UTC-4, Rich Jordan wrote:
> Customer has decided to turn off "legacy" DECnet support on their network. They currently use DECnet for copies between two nonclustered integrity servers that are on different IP subnets/VLANs and have Cisco doing whatever magic it does to make DECnet appear local. THis is Phase IV, not DECnet over IP. 
> 
> Is there any documentation on relative performance for bulk data transfer with preliminary data archiving (ie ZIP or backup to a local archive file so not transferring lots of individual files) on VMS using FTP/SFTP versus using NFS as the transfer mechanism? I know details matter and I don't have them yet but is one likely to be enough different that it is worth pursuing a test? Which won't be trivial given equipment availability... 
> 
> Thanks for any info
Rich,

As Robert noted, DECnet Phase V over IP is a viable choice. In situations where the client did not want to do that change, I have used sftp quite effectively, often in concert with ZIP/UNZIP.

As an example, in one quick test, I was able to transfer more than a terabyte of data in a reasonable time (I do not have the precise numbers in easy reach at the moment). The context was non-tape backup. The process was:
- Do BACKUP/IMAGE to a scratch device
- use ZIP "-V" to compress the BACKUP save set. Your mileage will vary, I was able to get approximately 90% size reduction.
- Use sftp to copy the resulting ZIP files to the destination machine
- UNZIP the transferred files
- use BACKUP to restore the saveset on the destination machine

The above was run in multiple BATCH jobs on both sides. 

-  Bob Gezelter, http://www.rlgsc.com