13 Replies Latest reply: Jan 2, 2012 12:48 AM by robinsc RSS

    Create ASM diskgroup on exadata

    772262
      Hi All,
      I am new to Exadata. I would like to create a database on Exadata sever. I am working on Quarter RAC.
      Please can I know how to create ASM disk group on ASM.

      Also how to check the space on Exadata. Is there any documentation which list commands/syntax to check on space, creating disk group etc.

      I cannot see any space when doing df -h

      [reidm@dm01db01 ~]$ echo $ORACLE_HOME
      /u01/app/oracle/product/11.2.0/dbhome_1
      [reidm@dm01db01 ~]$ df -h
      Filesystem Size Used Avail Use% Mounted on
      /dev/mapper/VGExaDb-LVDbSys1
      30G 16G 13G 56% /
      /dev/sda1 124M 19M 99M 17% /boot
      /dev/mapper/VGExaDb-LVDbOra1
      99G 21G 73G 23% /u01
      tmpfs 81G 196M 81G 1% /dev/shm
      /dev/sdb1 3.8G 3.5G 303M 93% /mnt/usb


      The machine config is
      [reidm@dm01db01 ~]$ uname -a
      Linux dm01db01.uklond6.savvis.net 2.6.18-238.12.2.0.2.el5 #1 SMP Tue Jun 28 05:21:19 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux


      Thanks,
      R
        • 1. Re: Create ASM diskgroup on exadata
          P.Forstmann
          You should able to use most of SQL statements for ASM documented in http://docs.oracle.com/cd/E11882_01/server.112/e18951/toc.htm but I am not 100% sure. Exadata documentation is not publicly available but you should have a copy with installation media.

          Better post to Exadata dedicated forum: Exadata
          • 2. Re: Create ASM diskgroup on exadata
            653696
            I have created ASM diskgroups using dbca

            Steps:
            1. Type dbca on the terminal. This will open DB configuration Assitant.
            2.Chose ASM(Configure Automatic Storage management ) option
            a. it may pop up mesg for configuring CSS.path of the script is also given.Execute it with root privileges.
            3.Click on create New
            4.Then click on show eligible candidates(It will show the eligible candidates)
            a. it will show the available unformatted free disk space.In case you dont have it.
            Add new/delete some disk.
            Use fdisk option to change Partition Table.Its menu driven .Type help n u will get all the available options


            5.Check the disk
            6.Click on create disk group --Disk groups will be created


            Hope this may help u a little
            • 3. Re: Create ASM diskgroup on exadata
              orawiss
              user5846399 wrote:
              Hi All,
              I am new to Exadata. I would like to create a database on Exadata sever. I am working on Quarter RAC.
              Please can I know how to create ASM disk group on ASM.

              Also how to check the space on Exadata. Is there any documentation which list commands/syntax to check on space, creating disk group etc.

              I cannot see any space when doing df -h

              [reidm@dm01db01 ~]$ echo $ORACLE_HOME
              /u01/app/oracle/product/11.2.0/dbhome_1
              [reidm@dm01db01 ~]$ df -h
              Filesystem Size Used Avail Use% Mounted on
              /dev/mapper/VGExaDb-LVDbSys1
              30G 16G 13G 56% /
              /dev/sda1 124M 19M 99M 17% /boot
              /dev/mapper/VGExaDb-LVDbOra1
              99G 21G 73G 23% /u01
              tmpfs 81G 196M 81G 1% /dev/shm
              /dev/sdb1 3.8G 3.5G 303M 93% /mnt/usb


              The machine config is
              [reidm@dm01db01 ~]$ uname -a
              Linux dm01db01.uklond6.savvis.net 2.6.18-238.12.2.0.2.el5 #1 SMP Tue Jun 28 05:21:19 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux


              Thanks,
              R
              hello,
              I believe it is the same syntax ; create diskgroup ...
              You can see the example here:

              http://guyharrison.squarespace.com/blog/2011/9/27/configuring-exadata-flash-as-grid-disk.html
              SQL>  
                1  create diskgroup DATA_SSD normal redundancy disk 'o/*/ssddisk*' 
                2  attribute 'compatible.rdbms'='11.2.0.0.0', 
                3  'compatible.asm'='11.2.0.0.0', 
                4  'cell.smart_scan_capable'='TRUE', 
                5* 'au_size'='4M'
              
              Alternatively you can use the database control for the ASM instance to create the new diskgroup.  Your new flash disks should show up as candidate disks.
              • 4. Re: Create ASM diskgroup on exadata
                772262
                thanks for the answer.
                I have to create 8 database with different size on Exadata server in differnet Oracle_Home.

                I would like to know how to list all the available gridcell and its size

                than I can create
                create griddisk TEST_DG_CD_00_cell03 celldisk='CD_00_cell03', size=100M (my question how do I know ''CD_00_cell03' cell list and its size)


                how do I create a ASM diskgroup using 'TEST_DG_CD_00_cell03' grisd disk.
                • 5. Re: Create ASM diskgroup on exadata
                  tychos
                  Hi,
                  Normally the exadata is already a prebuild appliance.
                  Can you check if you see an asm instance already up and running.
                  ps -ef | grep pmon
                  if so as oracle set your environment to the instance and do asmcmd.
                  Than you have a set of commands like lsdg to check your prebuild disk groups.
                  Regards,
                  Tycho
                  • 6. Re: Create ASM diskgroup on exadata
                    506787
                    The exadata documentation can be found in the following directory: /usr/share/doc/oracle/Exadata on the storage servers.

                    Generally, if you are new, it is best to work with the pre-configured configuration which generally is available after Oracle ACS has installed the Exadata for your company. That's also a great way to get an idea of how exadata looks like and how it works.

                    If for some reason the configuration is incomplete or does not work, first try to get it fixed.

                    Regarding the ASM diskgroups: after the initial configuration, all the disk space in exadata is consumed by 3 diskgroups, DATA_xxxx, RECO_xxxx and DBFS_DG, where 'xxxx' is the 4 letter machine prefix you or your company has chosen during install.
                    • 7. Re: Create ASM diskgroup on exadata
                      772262
                      I want to install 8 database 7 RAC and 1 single instance.

                      I would like to create separate diskgroup for each database. As per your reply if 3 disk group created by oracle consumes all the space, then I will not be able to create new disk group. So I have to use existing diskgroup.

                      Can this have a performance impact?
                      • 8. Re: Create ASM diskgroup on exadata
                        603349
                        user5846399 wrote:
                        I want to install 8 database 7 RAC and 1 single instance.
                        So you have a full rack, and want 1 database with 7 instances and 1 node with a separate database instance? Clarify if need be.
                        I would like to create separate diskgroup for each database. As per your reply if 3 disk group created by oracle consumes all the space, then I will not be able to create new disk group. So I have to use existing diskgroup.
                        So you want 2 diskgroups? Clarify if need be?
                        What is the requirement to have seperate diskgroups for each database?
                        Can this have a performance impact?
                        Certainly. Depending on how you implement them.

                        You will get much better advice if you explain why you want to do something (a.k.a. "the requirements") versus just asking if something is possible.

                        --
                        Regards,
                        Greg Rahn | blog | twitter | linkedin
                        • 9. Re: Create ASM diskgroup on exadata
                          772262
                          requriements are

                          7 RAC databases and 1 single instance on Exadata server

                          I would like to create separate ASM diskgroup for individual database.

                          Can I create different ASM diskgroup?

                          2nd question

                          What is the impact of separate diskgroup
                          • 10. Re: Create ASM diskgroup on exadata
                            603349
                            You simply repeated yourself -- you haven't provided any clarity to the questions I asked. There is help to be offered here, but more details are required.

                            --
                            Regards,
                            Greg Rahn | blog | twitter | linkedin
                            • 11. Re: Create ASM diskgroup on exadata
                              772262
                              I want to know
                              what is the best practice

                              create separate disk group for each database or put all the database on the same disk group?

                              All the database vary in size and functionality. Few of the database are datawarehouse and rest are all OLTP.
                              • 12. Re: Create ASM diskgroup on exadata
                                603349
                                Based on that level of detail, I'd say just use one ASM diskgroup.

                                Best practice is based on details about the system, unless you want the lowest common denominator, one size fits all answer, which may or may not be best for you.
                                Suggested reading on that topic: http://www.scaleabilities.co.uk/2011/09/16/right-practice/

                                The more details you can provide, the more the responses can be targeted for your specific requirements.


                                --
                                Regards,
                                Greg Rahn | blog | twitter | linkedin
                                • 13. Re: Create ASM diskgroup on exadata
                                  robinsc
                                  As you have only a quarter rack you only have 3 storage cells with their disks. It is certainly best to spread your i/o across all of them as eavenly as possible. The easisst way to do this is to use the standard layout of DATA and RECO and have all 7 +1 databases utilise the DATA asm diskgroup. this will ensure that the storage cells are equally utilised and i/o remains balanced.
                                  Thanks