Metrics Migration Tool - Cassandra

Charles Crouch ccrouch at redhat.com
Wed Jan 9 18:37:18 UTC 2013



----- Original Message -----
> After some lengthy discussion with Stefan, I think the migration tool
> needs to be run while the server is offline or possibly in
> maintenance mode. The best time to run the tool would be prior to
> running the RHQ installer. A problem with doing the data migration
> while the server is running is that we could wind up with skews in
> the aggregate data. The easiest and fastest way to ensure data is
> consistent for both pre- and post-upgrade is to run the data
> migration while the server is down.

Whether this approach is feasible or not could very well depend on the speed of the migration
-How long does our normal upgrade take today? I'm not aware of folks saying that was too long
-If it takes hours/days to move data during upgrade then that may simple not be an option. Could a portion of the data be moved while the server is live?

> 
> - John
> 
> On Jan 2, 2013, at 6:20 PM, Stefan Negrea <snegrea at redhat.com> wrote:
> 
> > Hello Everybody,
> > 
> > 
> > With new Cassandra based metrics storage system, existing data will
> > need to be migrated out of existing SQL storage to Cassandra. I
> > put together a simple design document for the data migration tool
> > that will be delivered with RHQ when the new metrics storage
> > system is completed.
> > 
> > 
> > My initial thoughts about the tool are:
> > 1) Restartable migration process, this will be especially useful
> > for users with large amounts of metrics.
> > 2) Favour robustness over performance because this migration will
> > be done only once.
> > 3) Make the tool external to the product (not part of the
> > installation), so user can do the migration ahead of the upgrade.
> > 
> > 
> > Here is the full design document:
> > https://docs.jboss.org/author/display/RHQ/Metrics+Data+Migration+-+Design
> > 
> > 
> > Feedback is more than welcomed since this tool is still in the
> > early planning stages.
> > 
> > 
> > 
> > Thank you,
> > Stefan Negrea
> > 
> > Software Engineer
> > 
> > _______________________________________________
> > rhq-devel mailing list
> > rhq-devel at lists.fedorahosted.org
> > https://lists.fedorahosted.org/mailman/listinfo/rhq-devel
> 
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