RE: Trying to wrap my head around TAF
- From: D'Hooge Freek <Freek.DHooge@xxxxxxxxx>
- To: "sacrophyte@xxxxxxxxx" <sacrophyte@xxxxxxxxx>, ORACLE-L <oracle-l@xxxxxxxxxxxxx>, Jeremy Schneider <jeremy.schneider@xxxxxxxxxxxxxx>
- 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:
(DESCRIPTION =
(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_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = dg-ip)(PORT = 1521))
)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = my_service_name)
(FAILOVER_MODE =
(TYPE = SELECT)
(METHOD = BASIC)
(RETRIES = 180)
(DELAY = 5)
)
)
)
Freek D'Hooge
Uptime
Oracle Database Administrator
email: freek.dhooge@xxxxxxxxx
tel +32(0)3 451 23 82
http://www.uptime.be
disclaimer
________________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] 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.
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS=(PROTOCOL=TCP)(HOST=primary1-vip.your.com)(PORT=1521))
(ADDRESS=(PROTOCOL=TCP)(HOST=primary2-vip.your.com)(PORT=1521))
(ADDRESS=(PROTOCOL=TCP)(HOST=standby1-vip.your.com)(PORT=1521))
(ADDRESS=(PROTOCOL=TCP)(HOST=standby2-vip.your.com)(PORT=1521))
)
(CONNECT_DATA =
(SERVER=DEDICATED)
(SERVICE_NAME=OMNI-SERVICE)
(FAILOVER_MODE =
(TYPE=session)
(METHOD=BASIC)
(RETRIES=180)
(DELAY=1)
)
)
)
References:
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@xxxxxxxxxxxxxx> 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!
See also:
http://www.ardentperf.com/2007/03/29/centralized-taf-configuration-in-10g-part-2/
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. :)
-Jeremy
On Fri, Jun 19, 2009 at 3:03 PM, Charles Schultz <sacrophyte@xxxxxxxxx> 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@xxxxxxxxx> 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
--
//www.freelists.org/webpage/oracle-l
Other related posts:
