Re: Data Guard - Fast Start failover
- From: kathryn axelrod <kat.axe@xxxxxxxxx>
- To: "D'Hooge Freek" <Freek.DHooge@xxxxxxxxx>
- Date: Thu, 27 May 2010 00:09:06 -0700
Thanks Freek.
Is it just for 11.2 or all of 11g?
I've seen documentation about it for 11.2
http://download.oracle.com/docs/cd/E11882_01/server.112/e10702/sofo.htm#DGBKR3548
but can't find anything referring to it on 11.1.
On Wed, May 26, 2010 at 11:41 PM, D'Hooge Freek <Freek.DHooge@xxxxxxxxx>wrote:
> Hi,
>
> On 11g, you don't need the trigger anymore. You can use srvctl (I think you
> need to install the infrastructure layer) to specify the role of the service
> and the dataguard broker will failover the necessary services.
>
>
> Regards,
>
>
> Freek D'Hooge
> Uptime
> Oracle Database Administrator
> email: freek.dhooge@xxxxxxxxx
> tel +32(0)3 451 23 82
> http://www.uptime.be
> disclaimer: www.uptime.be/disclaimer
> ________________________________________
> From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
> On Behalf Of kathryn axelrod
> Sent: donderdag 27 mei 2010 8:30
> To: Ram K
> Cc: oracle-l
> Subject: Re: Data Guard - Fast Start failover
>
> Hi Ram,
>
> Both actually. If you set up the observer with DGMGRL, you can only put it
> in one location. However, if you set it up with OEM (one of the
> few worthwhile features of OEM that doesn't cost extra), you get to set up a
> main observer And a backup observer. Thus if the main observer goes down,
> the backup takes over. Very nifty!
>
> As for the tnsnames, this too is pretty spiffy. I think it's easiest to
> explain with a setup example...
>
> Create your tnsnames:
> mydb =
> (DESCRIPTION=(ADDRESS_LIST=(LOAD_BALANCE=off)(FAILOVER=ON)(ADDRESS=(PROTOCOL=tcp)(HOST=host1)(PORT=1521))(ADDRESS=(PROTOCOL=tcp)(HOST=host2)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=mydb.mydomain)))
>
> Create a service:
> exec
> dbms_service.create_service(service_name=>'mydb',network_name=>'mydb');
>
> Create a trigger:
> after startup on database
> declare
> role varchar (30);
> begin
> select database_role into role from v$database;
> if role='PRIMARY' then
> dbms_service.start_service('mydb');
> else
> dbms_service.stop_Service('mydb');
> end if;
> end;
>
> The two issues with the failover connection are that the server changes and
> the db name changes. Without any special setup, one would need to have
> multiple tns strings or update their tns string after every failover.
>
> The above steps take care of these issues as the tns string makes it such
> that if mydb can't be found on host1, it looks for it on host2. (Thus it
> doesn't matter which server is housing the primary.) And the service
> name/trigger combo make it such that the primary db will always have the
> name of mydb (and the standby never will). (Thus as long as you are
> connecting to 'mydb', you Will be connecting to the primary.)
>
>
> Hope this helps..
> -k
>
>
> Side note ->
> We have yet to encounter any issues with DG (have DG on 9i, 10g, 11g and
> FSFO on 10g & 11g) but I did just come across note 972207.1 which is
> definitely worth reading before you pick your 11g version.
>
>
> On Wed, May 26, 2010 at 6:47 PM, Ram K <lambu999@xxxxxxxxx> wrote:
>
> Thanks Kathryn. Did you install the observer in the DR site or at a third
> site? Do the clients tnsnames need to be reconfigured in case of a failure
> when connecting to the new primary.
>
>
>
> On Wed, May 26, 2010 at 6:45 PM, kathryn axelrod <kat.axe@xxxxxxxxx>
> wrote:
> You wouldn't even need FSFO if you have two hours of allowed downtime :)
>
> FSFO works ~phenomenally~ well. Right now we have it running on 11.1.0.7
> with no issues...There is around 1minute of downtime if the primary crashes.
>
> The only thing I'd throw out there is there are a few 11.1.0.7 DG specific
> patches (see note 738538.1) that are recommended...Other than that, I
> truly love DG/FSFO; it is amazing.
>
> On Wed, May 26, 2010 at 3:41 PM, Ram K <lambu999@xxxxxxxxx> wrote:
> Hello,
>
> We are planning on a new HA/DR solution for a new application that we are
> building. Most of our databases sit on SAN which is synchronosuly
> replicated via SRDF to a DR site. The users for this application want 2
> hr window within which the DB needs to available if it goes down. The vendor
> recommends clustering, but I am also looking at Dataguard with Fast start
> failover. The physical standby can be at the DR site. The DB will be on
> 11g.
>
> Has anyone used 11g DG with FSF? Any specific issues? Does the DB come up
> quickly without any problem if the primary DB goes down?
>
> --
> Thanks,
> Ram.
>
>
>
>
> --
> Thanks,
> Ram.
>
>
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