DB2 10.5 HADR question
DB2 10.5 on Windows Server
I am using HADR to do a server migration. Old server is primary and new server is stand by. At migration time, I plan to shut down the primary and then make the standby primary. I am looking for some way to be sure that I don't lose any data when I do this.
Can I quiesce the primary before hand and do some type of flush log to make sure all the data has beem copied over to the standby? Or should I do a takeover by force on the standby and will that ensure no data loss?
Thank you!
Jim
I am using HADR to do a server migration. Old server is primary and new server is stand by. At migration time, I plan to shut down the primary and then make the standby primary. I am looking for some way to be sure that I don't lose any data when I do this.
Can I quiesce the primary before hand and do some type of flush log to make sure all the data has beem copied over to the standby? Or should I do a takeover by force on the standby and will that ensure no data loss?
Thank you!
Jim
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Hi,
Set write suspend would not work in this scenario.
You can either use
db2 force application (all)
or
QUIESCE db command
to gracefully force applications off the database and then shut them down.
Since you are upgrading the database between major versions (10.5 - 11.x), then a scheduled downtime where the applications are shut down prior to the upgrade is unavoidable.
Fixpack upgrades (in the same major version) are easier, using HADR rolling upgrade where applications can connect to the primary while the fixpack is applied to the standby. Then a switchover is done, and the previous primary is finally upgraded to the fixpack. Unfortunately, HADR rolling upgrade can not be done between major versions.
Regards,
Tomas Helgi
Set write suspend would not work in this scenario.
You can either use
db2 force application (all)
or
QUIESCE db command
to gracefully force applications off the database and then shut them down.
Since you are upgrading the database between major versions (10.5 - 11.x), then a scheduled downtime where the applications are shut down prior to the upgrade is unavoidable.
Fixpack upgrades (in the same major version) are easier, using HADR rolling upgrade where applications can connect to the primary while the fixpack is applied to the standby. Then a switchover is done, and the previous primary is finally upgraded to the fixpack. Unfortunately, HADR rolling upgrade can not be done between major versions.
Regards,
Tomas Helgi
QUIESCE instance ... restricted access command might work to stop applications from connecting to the database while you ensure that the LOGS are in sync.
However, I have to admit that I have not used that command when upgrading a database in my process as I have described earlier. And I have not checked what affect it has on the HADR sync process.
https://www.ibm.com/docs/en/db2/10.5?topic=commands-quiesce
https://datageek.blog/en/2016/12/13/starting-a-db2-instance-in-a-quiesced-state/
You always have to end up with, in the process, to change the db2 client to point to the new server. However, this might give you some space to work on the database without any connections interrupting or adding data to the database while you ensure that the logs on the primary and standby are in sync.
Regards,
Tomas Helgi
However, I have to admit that I have not used that command when upgrading a database in my process as I have described earlier. And I have not checked what affect it has on the HADR sync process.
https://www.ibm.com/docs/en/db2/10.5?topic=commands-quiesce
https://datageek.blog/en/2016/12/13/starting-a-db2-instance-in-a-quiesced-state/
You always have to end up with, in the process, to change the db2 client to point to the new server. However, this might give you some space to work on the database without any connections interrupting or adding data to the database while you ensure that the logs on the primary and standby are in sync.
Regards,
Tomas Helgi
The preferred menthod is shutdown the Primary, which leaves the Primary intact, and "takeover by force" the Standby. For concern of data loss, you can always check what is the last log being archived on the Primary and what is the last log being applied on the Standby.
Hi Jim,
Do you need more help with this?
Regards,
Tomas Helgi
Do you need more help with this?
Regards,
Tomas Helgi
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My main concern is I don't have the ability to stop the applications. And the developers can't due to some reason I am sure is legit. If I kill an application process, it will respawn before I can count to to.
So I need to make sure I can do the failover without losing data.
If I use
Open in new window
would that affect the standby server? If I can issue that and wait till primary and standby are synched then that would be perfect. With Quiesce I am afraid that as soon as I UnQuiesce it, the connections will renew before I can do anything else.Thank you!