[infinispan-dev] Cache migration (rolling upgrades, dump/restore, etc)

Martin Gencur mgencur at redhat.com
Mon May 22 08:59:57 EDT 2017


Hi Wolf,
that was exactly my thought. Clients redirected to the target cluster do 
not get updates written by other clients in the source cluster during 
the rolling upgrade process. It is because the clients in target cluster 
won't read the data through the remote cache store if they already have 
the requested key in the local memory. Is there a BZ/JIRA for this?

Martin

On 19.5.2017 13:17, Wolf Fink wrote:
> +1 for Vojtech
>
> yes the client's need to moved to the new cluster in one shot current, 
> that was discussed before.
> And it makes the migration because most of the customers are not able 
> to make that happen.
> So there is a small possibility of inconsistence if clients connect to 
> the old server update entries until the new server already migrated it.
>
> I see two options
> 1)
> source server need to propagate active to target on update
> 2)
> with the new L4 strategy all clients are moved automatically to the 
> target. So the source is not updated.
> I only see a small possibility for this to happen during switch
> - a client might still have a request to the source until other 
> clients are moved to target and already accessed the key
> - a new client connects with old properties, here we need to ensure 
> that the first request is redirected to the target and not update the 
> source
>
> On Fri, May 19, 2017 at 12:50 PM, Vojtech Juranek <vjuranek at redhat.com 
> <mailto:vjuranek at redhat.com>> wrote:
>
>     On středa 17. května 2017 16:56:25 CEST Tristan Tarrant wrote:
>     > 2) Need a way to "rollback" the process in case of failures
>     during the
>     > migration: redirecting the clients back to the original cluster
>     without
>     > data loss. This would use the above L4 strategy.
>
>     it's not only about redirecting clients - IIRC newly created
>     entries on target
>     cluster are not propagated back to source cluster during rolling
>     upgrade, so
>     we need also somehow sync these new data back to source cluster
>     during the
>     rollback to avoid data losses. Same applies to "cancel process"
>     feature
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