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    Implement Oracle ASM

    ASulthan

      Hi

       

      In our environment we have setup oracle 10g r2 and split with tablespace data different RAID and index Different RAID  to get better performance . now we  have to plan to move 11gr2 using with ASM.

       

      how to implement or use  same procedure with ASM

       

      Any help highly appericiated

       

      Thanks

        • 1. Re: Implement Oracle ASM
          Dude!

          ASM allows you create disk groups with external redundacy that could be using your existing RAID infrastructure. However, whether or not this would be your best option cannot be determined with the current information. ASM is not RAID and based on very different concepts. I suggest you read the ASM concepts guide to understand how ASM works.

          • 2. Re: Implement Oracle ASM
            Aritra-Oracle

            Hi Sultan,

             

            Yes, you can keep with same architecture.

            But ,before moving into production ,I would suggest to test same with 11gr2 on lower version.

             

            Regards,
            Aritra

            • 3. Re: Implement Oracle ASM
              ASulthan

              Thanks Aritra

               

              I will check and updated status asap.

               

              Thanks

              • 4. Re: Implement Oracle ASM
                Salman Qureshi

                Hi,

                1. Oracle's recommendation is to use external redundancy (I use 1+0) and discourages to use normal or high redundancy.

                2. Based on your database size and future growth, decide the LUN size you would present for ASM diskgroups. for terabyte sized databases, I use 1T LUN size, for normal sized, I use 256G LUN size

                3. Always use disks with same properties (in terms of speed and performance) and LUNs of equal size for ASM disks

                 

                Salman

                • 5. Re: Implement Oracle ASM
                  fuadar_oracle

                  you can still keep your current RIAD architecture and build Disk groups on top of this.

                  Just remember based on the RAID architecture match it with the redundancy level.

                  i.e for a externally mirrored solution use External Redundancy. If you have JBOD's depending on what level you are comfortable with use Normal or HIGH redundancy.

                  What you are also looking at is a ILM approach and you are essentially trying to put different access path data in different type of RAID groups.

                  based on your design you will need multiple disk groups to accomodate what you are trying to achieve

                  • 6. Re: Implement Oracle ASM
                    Aritra-Oracle

                    Hi,

                     

                    + We does not discourage normal/high redundancy.

                    With cheaper storage ,going with software level mirroring is rather a good idea .

                     

                    There is no performance impact comparing to external redundancy diskgroup.

                     

                    + As ASM does stripping ,it is always recommended to use same characteristics devices on same diskgroup.

                     

                     

                    Regards,

                    Aritra

                    • 7. Re: Implement Oracle ASM
                      Salman Qureshi
                      + We does not discourage normal/high redundancy.

                      Well, I was just quoting recommendation from Oracle otherwise there could be a lot of possibilities where you might prefer to use normal/high redundancy.

                       

                      Considerations for Oracle ASM Storage

                       

                      Following is what I found in above mentioned document


                      A LUN is a disk presented to a computer system by a storage array. Oracle recommends that you use hardware RAID functionality to create LUNs. Storage hardware RAID 0+1 or RAID5, and other RAID configurations, can be provided to Oracle ASM as Oracle ASM disks.


                      Salman

                      • 8. Re: Implement Oracle ASM
                        Dude!

                        ASM redundancy does not function on the level of RAID and does not mirror disks.

                        • 9. Re: Implement Oracle ASM
                          Aritra-Oracle

                          Hi Salman,

                           

                          If you are using normal/High Redundancy,ASM will mirror internally as per partnering of disks within separate failgroup.

                          Which 1-to-many in nature.

                           

                          That means,if any allocation unit is placed on one disk of failgroup ,other disk which partner to that disk on other failgroup will hold mirrored block.

                           

                          -- This way it does mirroring at software level ,not exactly same as OS level mirroring and does not depend upon OS level mirroring,independent of it.

                           

                          Regards,

                          Aritra

                          • 10. Re: Implement Oracle ASM
                            Dude!

                            ASM knows about Oracle database files and does variable stripping of data among disks in a disk group to provide optimal performance. ASM can provide data redundancy, such as normal or high using the free disk space of available failure groups. By default, each disk is a failure group.

                             

                            ASM works different compared to RAID systems, which mirror disk blocks of a fixed size usually 512 bytes regardless. ASM provides you with stripping and redundancy and an option to reconfigure the whole enchilada while the data is online. In comparison, you cannot re-size or reconfigure a hardware RAID without destroying the data and rebuilding the RAID volumes.

                             

                            The way I see it, a hardware RAID is optional and can provide additional data redundancy and performance on top of ASM.

                            • 11. Re: Implement Oracle ASM
                              Salman Qureshi

                              Hi,

                              You are just explaining how redundancy works in ASM and I don't disagree with that. I was merely suggesting what Oracle has recommended.

                               

                              Salman

                              • 12. Re: Implement Oracle ASM
                                Dude!

                                Yes, but what you are quoting is out of context and misleading.

                                 

                                I'm not aware that Oracle recommends not to use ASM redundancy such as normal or high and instead rely on external RAID redundancy. Which is what this thread is about.

                                 

                                You also previously wrote:

                                 

                                1. Oracle's recommendation is to use external redundancy (I use 1+0) and discourages to use normal or high redundancy.

                                 

                                Where do you read this?

                                 

                                According to Oracle: Use Oracle ASM mirroring redundancy when not using hardware RAID.

                                 

                                Of course you should have some some redundant storage for your database, but one does not exclude the other. If you can afford it, use both and have additional redundancy and perfomance features.

                                • 13. Re: Implement Oracle ASM
                                  Aritra-Oracle

                                  Hi Salman,

                                   

                                  You might missed some small things,

                                   

                                  + RAID might have been suggested if you use external redundancy ,as ASM does not do mirroring in this type of diskgroup.

                                   

                                  But,I would suggest ,if disk can be accommodated ,use normal redundancy which will give you more control and better protection to your data.

                                   

                                  Regards,

                                  Aritra

                                  • 14. Re: Implement Oracle ASM
                                    Salman Qureshi

                                    Hi,

                                    I don't know whether I am missing some point or I am not able to make you understand what I saying .

                                    I just said what Oracle "recommends" to use (Hardware RAID and external redundancy), otherwise I don't disagree with you, that in several cased, normal or high redundancy will be handy and easier and cheaper. 

                                     

                                    Salman

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