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Is it OK to start app servers before JTS server?


Martin Lauridsen (1211211) | asked Apr 23 '12, 3:07 a.m.
In our current setup we have JTS/RTC/RQM on 3 separate machines. This complicates the nightly backup a bit. Currently, we use the same scripts on all three machines: 1 script shuts down the server, 1 script backs up data and db2 databases and the last script starts the server. These scripts are set to run with X minutes intervals.

However, we found it may occur that db2 backup is still under way, when the script to start the server is executed. Thus, we want to merge the backup script with the startup script, so it does not start the server until the db2 backup is complete.

ON THAT NOTE, I want to ask if it is OK, that the backup scripts are not interconnected between the servers, such that, for example it can happen that the RTC server is started before the JTS server to which it is registered.

Thank you

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Ralph Schoon (63.1k33645) | answered Apr 23 '12, 3:28 a.m.
FORUM ADMINISTRATOR / FORUM MODERATOR / JAZZ DEVELOPER
Hi,

we tried to outline the process here: https://jazz.net/library/article/795

I would not be concerned about the order of bringing up the servers. However, make sure the order of the back ups is not violated between JTS and the other apps. The important part is stopping the servers, not bringing them back up again.

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Martin Lauridsen (1211211) | answered Apr 23 '12, 3:37 a.m.
Hi,

we tried to outline the process here: https://jazz.net/library/article/795

I would not be concerned about the order of bringing up the servers. However, make sure the order of the back ups is not violated between JTS and the other apps. The important part is stopping the servers, not bringing them back up again.


Hi Ralph,
I see you have beefed up the article a bit. I was reading through the one located at https://jazz.net/library/article/547 (perhaps you should consider linking this to the former?). I will read through the one of Feb 20, 2012 now. Hopefully it resolves any questions I might have.

Thank you

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Ralph Schoon (63.1k33645) | answered Apr 23 '12, 4:43 a.m.
FORUM ADMINISTRATOR / FORUM MODERATOR / JAZZ DEVELOPER
Hi Martin,

you are right, I should add a statement and link into the older article. It fell trough the cracks. I will try to.

Thanks,

Ralph

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Martin Lauridsen (1211211) | answered Apr 23 '12, 9:00 a.m.
Hi Martin,

you are right, I should add a statement and link into the older article. It fell trough the cracks. I will try to.

Thanks,

Ralph


Hi Ralph,

I have now read through the document, and the only place I see something to worry about is: "To avoid conflicts and ensure consistency, the databases for all registered applications must be backed up to a point in time equal or earlier than the JTS database. In the example topology, this holds for the CCM as well as the QM database."

As I read this, the CCM and QM databases must be backed up no later than the JTS database. I am not sure if this applies when we are talking offline backups? If CCM and QM databases/servers are taken offline no later than the JTS server/database, shouldn't we be golden, even though some application server might go online before others are finished backing up? I don't think the document clearly answers that question for me. However, you hinted that it is the process of going offline that matters more than going online.

Thank you in advance
Martin

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Ralph Schoon (63.1k33645) | answered Apr 23 '12, 10:35 a.m.
FORUM ADMINISTRATOR / FORUM MODERATOR / JAZZ DEVELOPER
Martin,

the key point is the order. If you bring down the applications before the JTS (or all at once) you should be fine.

The issue happens during restore. If for example LDAP sync creates users in JTS. JTS creates these in the registered RTC and RQM applications.

If you restore JTS to a point where the users where not yet created and the applications to a point where they are, you will get problems, once JTS syncs with LDAP again.

I think you can create that with an offline backup. Bring down JTS, do the backup. Some hour later JTS is up again. If you now start doing the App backups you could create the situation.

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