5 Replies Latest reply: Mar 30, 2012 8:55 AM by empee RSS

    Many databases in same RAC

    505789
      How would you structure it to have 3 databases in two nodes?

      Having a single ASM home and 3 Oracle homes is the best thing to do, isn't it?

      Only one oracle user? Or 3 with different variables?

      Thank you for your opinions.
        • 1. Re: Many databases in same RAC
          912595
          usersp wrote:
          How would you structure it to have 3 databases in two nodes?

          Having a single ASM home and 3 Oracle homes is the best thing to do, isn't it?

          Only one oracle user? Or 3 with different variables?

          Thank you for your opinions.
          You will always have Single ASM Instance running in single machine. For e.g. in two node RAC database cluster, you will have ASM1 on node 1 and ASM2 on node 2. You cannot have ore then one ASM instance running on one machine. ASM can handle n numbers of database instances and all these databases instance connect/request to single asm instance.

          Its better to have single OS user for all 3 databases. If yo have different DBA's managing different database then you can have different OS user(Separate roles). But single is OK you only manage all.

          Now comming to oracle homes - Its better to have different home for each oracle database (Of course asm home will be different in all case) for management/availability/patching purposes. For e.g having different oracle homes will avoid affecting all other database if anything goes wrong in patching.
          Other e.g would be if you want to patch 1st database and other 2 database can remain online if you have different oracle homes.
          • 2. Re: Many databases in same RAC
            505789
            And once installed, how can you tell which Oracle home belongs to which SID?

            From /etc/oratab?
            • 3. Re: Many databases in same RAC
              empee
              Now comming to oracle homes - Its better to have different home for each oracle database (Of course asm home will be different in all case) for management/availability/patching purposes. For e.g having different oracle homes will avoid affecting all other database if anything goes wrong in patching.
              Other e.g would be if you want to patch 1st database and other 2 database can remain online if you have different oracle homes.
              I believe there are situations where having a multiple databases running out a single Oracle Home is better as it requires less OS level storage and reduces the number of homes that have to be patched. As ever, "it depends" on what your constraints are :-)
              • 4. Re: Many databases in same RAC
                912595
                empee wrote:
                Now comming to oracle homes - Its better to have different home for each oracle database (Of course asm home will be different in all case) for management/availability/patching purposes. For e.g having different oracle homes will avoid affecting all other database if anything goes wrong in patching.
                Other e.g would be if you want to patch 1st database and other 2 database can remain online if you have different oracle homes.
                I believe there are situations where having a multiple databases running out a single Oracle Home is better as it requires less OS level storage and reduces the number of homes that have to be patched. As ever, "it depends" on what your constraints are :-)
                Ok that also can be the case.. But would you risk all 3 database if anything goes wrong with binaries? I think doing some extra bit of work would be worth then having trouble with all three db
                • 5. Re: Many databases in same RAC
                  empee
                  You might not have a choice about how much storage you have available for OS and binaries, i.e., Exadata. Or you might have a large number of test databases for a particular system and not want the overhead of a separate home for each. I'm not saying that I would always run all my databases, for a given version, out of a single home, but rather that there is a case for each.