Shadowing between Caché 5.0.21 and 2016.2.0?

Question

Question

Heikki Koivulehto · Oct 26, 2016

#Caché #Compatibility #Databases #Distributed Data Management #Backup #Journaling

We are finally planning to migrate some ancient Caché applications that are run on Caché 5.0.21 to a new server with Caché 2016.2.0 or so.

I wonder if we could use Shadowing between those to keep the data on the new server up to date?

We would copy the Caché backup from the old environment to the new and do a RESTORE there and then start shadowing.

I know than 5.0.21 is no more officially supported by ISC.

Discussion (5)0

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Anzelem Sanyatwe · Oct 26, 2016

Hi Heikki;

I just recently been faced with the same situation you are in. I doubt it shadow is supported between those two versions, you can check it here 4) Supported Version Interoperability http://docs.intersystems.com/documentation/ISP/ISP-20162.pdf

The method we used was a Full Backup on old system and a restore on the new system just before the Migration day, and then during the downtime after users are stopped in the migration window we did a cumulative backup and restore (1, the cumulative backup and restore minimizes downtime 2, it's quick to copy over - as it is smaller). This plan worked well for us.

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John Murray · Oct 27, 2016

That'd rely on 2016.2.0 being able to restore the journals written by 5.0.21, right? I'm not saying that's not possible, just that it'd need to work correctly (i.e. not just appear to work).

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score 0 · Answer 1 · 2016-10-27T01:01:41-04:00

Thanks for your thoughts :)

I've got another idea: Why not just copy a full backup file to the new server and do a restore there a day or two before the migration and then during the downtime copy the journals that were created after the backup and restore them.

No need for an extra backup :)

Just have to take care of the journals and not to delete them too often.

score 1 · Answer 2 · 2016-10-27T05:04:25-04:00

Heikki Koivulehto · Oct 27, 2016

John,

According to the Interoperability table the backups and journals of 5.0 can be restored on 2016.2.

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score 0 · Answer 3 · 2016-10-28T09:36:51-04:00

Journal route wasn't an option for me. They were just too much and too many to copy (this due to the nature of the application) compared to the smaller one cumulative backup I mentioned. It also depends on whether you are looking at continuous trickling of transactions to the new system or a once off restore.