Re: RAC 12.2 - singleton service balancing

Hi,

unfortunately I have made a wrong assumption in my last mail:

" In admin managed databases/services I could set a preferred node, and the service would always return to this node, as soon as it is available again." Thats simply wrong, even with a preferred node set, the admin managed service will NOT jump back:

from the 2-day RAC Guide: If a service fails over to an available instance, then the service is not moved back to its preferred instance automatically. However, you can automate the relocation of a service to its preferred instance by using a callout. For more information about callouts, see "About FAN Callouts". An example callout script for relocating services back to their preferred instances is available on Oracle Technology Network at: http://www.oracle.com/technetwork/database/enterprise-edition/twpracwkldmgmt-132994.pdf (Thanks Troy for the hint and the link!)

My newly found "solution" for admin managed databases is simpler, though unsupported, and works like a charm:

<use at your own risk>
srvctl add service -db mydb -service myservice -preferred mynode1 -available mynode2 crsctl modify res ora.mydb.myservice.svc -attr "PLACEMENT=favored,ACTIVE_PLACEMENT=1,CHECK_INTERVAL=1,RELOCATE_KIND=offline,SERVER_POOLS=*,HOSTING_MEMBERS=mynode1" -unsupported </use at your own risk>

I love CRS - it can do more than Oracle wants. :)

-- 
Martin Klier | Performing Databases GmbH 
Managing Partner | Senior DB Consultant 
Oracle ACE 

martin.klier_at_performing-db.com | http://www.performing-databases.com 



> Von: "Martin Klier - Performing Databases GmbH" <martin.klier_at_performing-db.com>

> An: oracle-l_at_freelists.org

> Gesendet: Donnerstag, 11. Mai 2017 12:13:09


> Betreff: RAC 12.2 - singleton service balancing





> Hi listers,





> we have the need to run 12cR2 database services as singleton services on a RAC


> (that's a hard fact, please take that as given).




> According to the documentation, a singleton service will not return to its


> original location, when a node stops/restarts. That means in a 2-node-RAC, that

> booting a node will concentrate all load on one server, and I have to

> redistribute them manually again after we have the second node online again.




> In admin managed databases/services I could set a preferred node, and the


> service would always return to this node, as soon as it is available again. In

> 12.2 with a policy managed database, I can't have an admin managed service for

> this DB. I can even understand why, but what I am missing now is an option to

> rubber-wire a DB service to a node / instance.




> The logic of server pools also prevents me from having a node joining a pool


> only if the second node is away, at least as far as I came with my tests.




> I appreciate any idea, as long as I don't have to start the same service name on


> more than one node at the same time.




> Thank you very much in advance!





> --

> Martin Klier | Performing Databases GmbH


> Managing Partner | Senior DB Consultant

> Oracle ACE




> martin.klier_at_performing-db.com | http://www.performing-databases.com



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