Pythian Video: Oracle RAC — Why VIPs?

May 28, 2009 / By Alex Gorbachev

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“Seeing it once is better than hearing about it a thousand times” — I think this is the closest translation from one Russian proverb. I may add that hearing and seeing might be often better then reading so let me try to start a series of small videocasts about Oracle database technology.

One of the topics that beginners RAC DBA’s (along with network engineers supporting Oracle database infrastructure) are confused about is the Virtual IP usage in Oracle RAC starting from Oracle Clusterware 10g.

With this videocast, I will try to clarify those concerns once and for all. I have embedded the video here in a smaller window so you might want to go directly to YouTube for the full-size version of “Pythian Video: Oracle RAC – Why VIPs“.

This is an experiment for now so let’s see how it goes. Let me know if you find this format useful and don’t forger to rate it on YouTube. Note that if you don’t leave any comments here, I’d never know whether you liked it or not so don’t be shy and comment away…

29 Responses to “Pythian Video: Oracle RAC — Why VIPs?”

  • Hi Alex,

    Nice presentation.
    One little remark which may confuse people – on the last page you are talking about using VIP and not hostnames. In my opinion you should use “VIP hostname” instead of just VIP. It will be additional information for users that VIP has to be added to any name resolving system (DNS or local hosts files).
    As you know in case of server load balancing you can be redirected to other node and your connection description will have a “VIP hostname” instead of VIP IP.

    regards,
    Marcin

  • Alex,

    I quite liked this overview, thanks for creating a video!

  • Suresh says:

    Awesome Alex :)

  • Danyc says:

    Very nice, Alex!!!
    Keep going, it’s very helpful.

  • Alex Gorbachev says:

    @Marcin: I would actually argue with you on “VIP hostname” but yeah I’ve got your point re alias resolution. But as I said – it’s a good topic for the next session. :) I was talking about it in one of my presentations and will definitely make videocast about it.

    Everyone replied, thanks for your feedback.

  • I spend some time fixing issues related to not resolving VIPs name and there is why I always thing about that. I don’t remember a exact version of RAC but it was a bug and listener send both – vip and not-vip names to client in case of LB.

    regards,
    Marcin

  • Alex Gorbachev says:

    Marcin, I know a very good reason for that to happen (VIP resolution) and I saw it all the time due to misconfiguration. I’ll go over it next time. In the meantime, if you could provide the bug# – would be great.

  • Hi Alex,

    Here is a Metalink note about that
    342419.1

    I have got this in 10.2.0.3 and it
    is working without suggested workaround in 10.2.0.4.

    regards,
    Marcin

  • Alex Gorbachev says:

    Marcin,

    Right, this is what I was talking about. This is not a bug and it has a simple explanation. It’s the same in 11g and I described it in number of my presentations. Well, the next videocast is in order…

    Again, thanks for your feedback.

    Cheers,
    Alex

  • Alex,

    I have tested that issue on two RAC’s
    10.2.0.3 on Windows and 10.2.0.4 on Linux.
    On Windows I had to set a LOCAL_LISTENER to avoid return a pure hostname in case of LB. In 10.2.0.4 on Linux it is working with LOCAL_LISTENER set to empty string.

    Maybe it is platform depended – Windows is a little bit strange machine in case of resolving back IP into name and vice versa.

    regards,
    Marcin

  • Steven Peterson says:

    Nice presentation, thanks Alex.

    I didn’t realize that when a vip failed over it wasn’t actually recognized by the listener. Interesting…

    Looking forward to the next video.

  • […] The first videocast was quite popular — it has more than 300 views in couple weeks and considering no Hollywood stars were starring in that video and there were no nude scenes, I think it’s fair to say that this format was very much welcomed by the audience. […]

  • Karen McKee says:

    Very effective presentation. I’ve been working with RAC for several years and did not quite understand VIP. Now I feel much more confident.

  • hrishy says:

    Hi Alex

    Excellent presentation is it possible to do the video of the presentation under the hood of oracle clusterware here ?

  • Alex Gorbachev says:

    @hrishy: re under the hood of Oracle clusterware – yes most probably. I’ll probably do it in small bits to fit into content limitation so it would be more like a series just like with VIP’s.

  • hrishy says:

    Hi Alex

    excellent i appreciate the response and also the pain to take the time out and redo the video for the presentation under the hood of oracle clusterware

  • Rajesh says:

    Hi Alex,
    Excellent presentation. Concept is very well explained.

  • George says:

    This was a very good way to explain a complex subject. Short and sweet. That’s about all I can fit into a busy schedule. Keep them coming!

  • Alberto Dell'Era says:

    Very interesting, I really appreciated the “live demo”, something that cannot be got from the documentation, obviously. Thanks!

  • Mayank says:

    Great job , please post more RAC videos

  • Rommel says:

    Hi Alex,
    Thanks for this presentation. It’s perhaps the most succinct explanation I found in VIP.

    I just want to ask if it is possible for a node to have more than 1 VIP. In our RAC, we added a third NIC and we wanted to add a second VIP to listen in another subnet. I tried using ‘srvctl add nodeapps’ to bind the new NIC but instead of getting a new VIP, it replaced the current VIP setting instead.

    Is it possible to add a second VIP?

    Cheers.

    • @Rommel: There can only be one node VIP per node. You can can make two interfaces public and Clusterware will bring VIP up on any of them. However, not at the same time.
      You can configure User VIP but it’s different from node VIP and is designed to be used as part of non Oracle resource to be configured in HA like Apache web-server.

  • Sanjay Gupta says:

    Brilliant I appreciate the live demo, something that cannot be got from the documentation!

  • Antony says:

    Thanks; I found it helpful but the pace of presentation was on the speedier side :)
    that was either intentional or I am just slow

  • Sridhar Dondeti says:

    Put in much simpler way yet precise ..
    superb presentation.

  • karthi says:

    Presentation is very good. I have one doubt. Please clarify me.
    I have found in some tutorial and they mentioned as RE-ARPS Protocol. what is the meaning of RE-ARPS. RE-ARPS Stands for Reverse Address Resolution Protocol or Address Resolution Protocol.

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