RE: Trying to wrap my head around TAF
Date: Wed, 15 Jul 2009 16:47:14 +0200
Not whith the dg broker, but following comes from a setup with rac (2 nodes) with a single node standby:
(LOAD_BALANCE = OFF) (FAILOVER = ON) (ADDRESS_LIST =)
(LOAD_BALANCE = ON)
(FAILOVER = ON)
(ADDRESS = (PROTOCOL = TCP)(HOST = rac-node1-vip)(PORT = 1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = rac-node2-vip)(PORT = 1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = dg-ip)(PORT = 1521))
(SERVER = DEDICATED)
(SERVICE_NAME = my_service_name)
(TYPE = SELECT) (METHOD = BASIC) (RETRIES = 180) (DELAY = 5) )
Oracle Database Administrator
tel +32(0)3 451 23 82
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Charles Schultz Sent: woensdag 15 juli 2009 16:38
To: ORACLE-L; Jeremy Schneider
Subject: Re: Trying to wrap my head around TAF
I filed a case with Oracle and did some minor testing - my biggest roadblock is that I do not yet have a test system with both the DG broker and RAC, I have one for each.
So, I will throw this out there and hope that someone with a DG-broker-enabled RAC environment can verify. =) I have yet to find any documents that puts these two concepts together. My ears/eyes are open to recommendations.
I tried with multiple DESCRIPTIONs (ie, in order to have different LOAD_BALANCE or FAILOVER_MODE parameters), but apparently TAF works best with one. Expounding on Jeremy's connection string (as well as the ones mentioned in the metalink notes), one can throw all nodes that provide the listed service in one ADDRESS_LIST, whether they be standby or clustered. The key part is a database trigger that turns off the service for standby instances such that the LOAD_BALANCE option will never even consider the listener on that node since PMON will not communicate anything about the service.
(TYPE=session) (METHOD=BASIC) (RETRIES=180) (DELAY=1) )
Metalink note 461874.1 "Failover Connections for Data Guard Error with ORA-1033" Metalink note 316740.1 "How to configure to let TAF work after Data Guard Switchover or Failover" Client Failover in Data Guard Configurations for Highly Available Oracle Databases
On Mon, Jun 22, 2009 at 11:52, Jeremy Schneider <jeremy.schneider_at_ardentperf.com> wrote: "Server-side TAF" is a reference to storing the TAF configuration info in the server, and having the client pull it down at connect-time. Not well documented, but very interesting. Look out for surprising rules of precedence - the server configuration always over-rides the client tnsnames.ora!
I've configured TAF for automatic failover to a standby (along with dataguard broker automatic failover) -- but I haven't configured TAF for both RAC and DG in the same database. It would be cool to hear if someone else out there on the list has done this. :)
On Fri, Jun 19, 2009 at 3:03 PM, Charles Schultz <sacrophyte_at_gmail.com> wrote: For #2, I do see table 95-3, but I missed how it specified "server-side TAF". How does a server transparently failover?
On Fri, Jun 19, 2009 at 14:56, Charles Schultz <sacrophyte_at_gmail.com> wrote:
2) Similar to this, I am trying to understand the different TAF parameters used in dbms_service.create_service. The documentation has very little to say about them (just the bare bones - the 11g documentation is exactly the same I think), and when one implicitly creates a service by modifying the SERVICE_NAMES parameter, all the parameters default to null (according to dba_services). Are those TAF parameters actually used, or are they merely place-holders for "future" functionality? If they do play a role in TAF, what and how?
-- Jeremy Schneider Chicago, IL http://www.ardentperf.com/category/technical -- Charles Schultz -- http://www.freelists.org/webpage/oracle-lReceived on Wed Jul 15 2009 - 09:47:14 CDT