Re: Regarding RAC vip failover and tnsnames entry

Hi Bradd

   I guess, I must be missing something here. Typically, when VIPs are
failed over to surviving node, failed VIPs will have no listeners running.
Since there is no listener, server side redirection will not happen, I
think.

 (or)  May be, you are configuring listeners in failed over VIPs?

Cheers
Riyaj


On Mon, May 11, 2009 at 1:03 PM, Bradd Piontek <piontekdd@xxxxxxxxx> wrote:

> Not to sound contradictory (although I am contradicting what Riyaj wrote),
> but the 2nd node is note 'required' to be in the tnsnames.ora if Server-Side
> Load balancing is in place and you are using the VIP address. All listeners
> on all nodes know of the other listeners, and can re-route traffic to a
> different node. What is required is that the DNS entry spit back to the
> client from the listener needs to be able to be resolved by the client.
> As with just about anything, especially with RAC, it is important that you
> test out all these types of scenarios and see how your application reacts to
> these types of events.  (regardless of what the manual says 'should'
> happen). Just $0.02.
>
>
> Bradd Piontek
>   "Next to doing a good job yourself,
>         the greatest joy is in having someone
>         else do a first-class job under your
>         direction."
>  -- William Feather
>
>
>
> On Mon, May 11, 2009 at 12:53 PM, Riyaj Shamsudeen <
> riyaj.shamsudeen@xxxxxxxxx> wrote:
>
>> Hi Sanjeev
>>
>> >> Is it required to have second node entry in tnsnanames.ora for
>> connection to work
>> >> after vip failover.
>> Yes, you need to have second node entry also in your tnsnames.ora file.
>>
>> You might want to understand what problems VIPs are resolving. Let's say
>> that a new connection request is made and for some reason IP address in that
>> tnsnames entry is not available and so, there is no response from that IP.
>> Connection request will wait for TCP connect timeout parameters (typically
>> 3-10 minutes controlled by tcp parameters), then try next entry in the
>> tnsnames list.
>>
>> By failing over VIP to surviving nodes of the cluster, there will be an
>> immediate response, essentially as, 'no listener'. So, connection request
>> will try next entry in the tnsnames entry immediately avoiding tcp connect
>> timeout delays.
>>
>> HTH
>>
>> Cheers
>>
>> Riyaj Shamsudeen
>> Principal DBA,
>> Ora!nternals -  http://www.orainternals.com
>> Specialists in Performance, Recovery and EBS11i
>> Blog: http://orainternals.wordpress.com
>>
>>
>>
>> On Mon, May 11, 2009 at 12:08 PM, Syed Jaffar Hussain <
>> sjaffarhussain@xxxxxxxxx> wrote:
>>
>>> Sanjeev,
>>> When a node fails, the VIP associated with failed node is automatically
>>> fail over to one of other nodes exists in the cluster.
>>>
>>> The existing connections will typically receive ORA-3113 errors and the
>>> new connections using address list will select the next entry in the list.
>>>
>>>
>>>
>>> On Mon, May 11, 2009 at 9:39 AM, sanjeev m <sanjeevorcle@xxxxxxxxx>wrote:
>>>
>>>> All,
>>>>
>>>> We have two node RAC environment with the applications connections going
>>>> to first node.
>>>> (No reference to the second node in tnsnames.ora). We are not using load
>>>> balancing or failover.
>>>>
>>>> If case of nic failure on first node CRS on the other node will failover
>>>> the vip (raising event and bringing up the resource online on second node)
>>>> and re-arp the machine address on the network.
>>>>
>>>> Question:
>>>>
>>>> (a) Existing connections: They will get an errors saying the instance is
>>>> down.
>>>> (b) New connections:  They will be able to connect to vip on second node
>>>> (with reference to firsthostname-vip entry in tnsnames.ora).
>>>>
>>>> Are both (a) and (b) true. Is it required to have second node entry in
>>>> tnsnanames.ora for connection to work after vip failover.
>>>>
>>>> Regards
>>>>
>>>
>>>
>>>
>>> --
>>> Best Regards,
>>>
>>> Syed Jaffar Hussain
>>> Oracle Certified Master (10g)
>>> http://www.oracle.com/technology/ocm/shussain.html
>>> Oracle ACE
>>>
>>> http://apex.oracle.com/pls/otn/f?p=19297:4:1579866181463918::NO:4:P4_ID:126
>>> OCP 8i,9i & 10g DBA
>>> RAC Certified Expert
>>> Official Oracle RAC SIG Representative for Saudi Arabian region  (
>>> http://www.oracleracsig.org/)
>>> I blog at
>>> http://jaffardba.blogspot.com/
>>> --------------------
>>> "Winners don't do different things. They do things differently."
>>>
>>
>>
>

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