5 Replies Latest reply: May 10, 2012 8:24 AM by 877440 RSS

    question

    877440
      thanks.
        • 1. Re: question on how to present AIX asm disks to Linux server -xxs transportable
          Levi Pereira
          Angelina wrote:
          Hi, I have to ask a question here.

          I planned to use cross-platform transportable tablespaces methods to migrate a production database of 1tb.

          On Source db, we have database on AIX asm disks. On target, it is linux asm.

          How do we present AIX asm disks to be visible to LInux sever?

          My storage team proposed to take a snapshot of the disks and then let SA to present those snapshot disks to Linux.

          My question here is how the rman convert process recognize those disks?
          Hi,

          No, It is not possible because RMAN convert only files. The ASM filesystem cannot be converted because not exists a tool to do that.

          I already tried mounting Luns of AIX no Linux and get failed.

          See this test:

          Created disk file called DATA01 with dd command and created a Diskgroup named DATA_MOVE on AIX.

          For each block on ASMDISK Oracle configured parameter “kfbh.endian:0 ; 0×000: 0×00″ . Endian =0 means BIG ENDIAN / Endian =1 means Little ENDIAN)

          Check first 80 or all ASM blocks.
          for i in {0..80};
          do
          echo blknum $i
          kfed op=read dev=DATA01 blknum=$i |head -1
          done
          So, when Oracle format ASMDISK all blocks have configured OS Endian. So, when you try mount the LUN from AIX on Linux ASM will not reconize that LUN as ASMDISK.

          So, Mounting LUNS (ASMDISK) from AIX on Linux (i.e with different ENDIAN format) won't work.

          You must convert the files to a normal filesystem (ex: jfs) and move the files over network to Linux using some resource (e.g NFS, SCP,FTP, etc)


          Regards,
          Levi Pereira
          • 2. re:
            877440
            ok.
            • 3. Re: question on how to present AIX asm disks to Linux server -xxs transportable
              Levi Pereira
              Hi Angelina,
              So how to achieve that?

              The reason we want to is to minimize the downtime. I only allocated 4 hrs total to do the migration of 1 tb database. Expdp was extremely slow.
              From Oracle Whitepaper:

              Moving the Datafiles
              There are multiple ways to move the datafiles to the target system.

              ASM datafiles:
              • Reconfigure the SAN so that the storage devices can be mounted directly on the target system. Refer to your storage vendor for operating system specific details.

              • Use the PL/SQL DBMS_FILE_TRANSFER package to transfer datafiles from the source instance to target instance. See the Oracle Database
              Administrator’s Guide [5] for details.

              • Use XML DB FTP capability to ftp datafiles from the source instance to the target instance. See the Oracle XML DB Developer’s Guide [9] for details.

              • Use RMAN to move datafiles to a staging area on the source system, use standard operating system tools to transfer datafiles to the target system, and then use RMAN to move the files into ASM on the target system. See the Oracle Database Backup and Recovery Advanced User’s Guide [6] for details.

              Here is not explaining situations where the endian is different. Just said: "Reconfigure the SAN so that the storage devices can be mounted directly on the target system.  Refer to your storage vendor for operating system specific details."


              Continuing from Oracle Whitepaper:

              From any filesystem (not ASM)

              Mount the storage that contains the datafiles on the target system

              XTTS requires two operations on the datafiles: conversion to the target platform endian format and transfer to the target system.
              Typically these operations occur as separate steps.

              For example, when performing a target system conversion, the datafiles are first transferred to the target system, and then converted using the RMAN CONVERT command in a separate step. However, these two operations can occur in a single step if you mount the source datafile location on the target system.

              For example:

              Example 1: This scenario involves rezoning a storage area network so that the volumes containing the datafiles are available to the target system (read-only mode is sufficient). When the file conversion is run, the output of the RMAN CONVERT command places the datafiles in their final location without the need for a separate transfer Platform Migration step.
              The supportability of rezoning storage between platforms is operating system dependent.  Contact your storage vendor for details.

              Note: Far as I understood the word "storage" here mean "filesystem".


              Example 2: This scenario involves NMS mounting the source filesystem containing the datafiles on to the target system. When the file conversion is run on the target system, RMAN CONVERT reads from the NFS mount and places the converted datafiles in their final location without the need for a separate transfer step.

              Example 3: This scenario involves NMS mounting the target filesystem that will be the final location of the converted datafiles onto the source system. When the conversion is run on the source system, the RMAN CONVERT command reads from the original datafile location and places the converted datafiles on the NFS mounted final location without the need for a separate transfer step.


              I suggest you open a SR to check this issue. I'm pretty sure it does not work.
              What is the best way to achieve minimum downtime?
              You have many options, the best way to get minimun downtime is use golden gate.

              On this whitepaper give to you many options:
              http://www.oracle.com/technetwork/database/features/availability/maa-wp-11g-platformmigrationtts-129269.pdf

              Also check:

              Master Note for Transportable Tablespaces (TTS) -- Common Questions and Issues [ID 1166564.1]

              How to Move Tablespaces Across Platforms Using Transportable Tablespaces With RMAN [ID 371556.1]

              Regards,
              Levi Pereira
              • 4. Re: question on how to present AIX asm disks to Linux server -xxs transportable
                Levi Pereira
                Hi,

                Little note:
                Using RAW Devices during migration can avoid copy over LAN. You can test it to make sure will work.

                eg
                 CONVERT TABLESPACE DATA_MOVE
                 TO PLATFORM = "Linux x86 64-bit"
                 DB_FILE_NAME_CONVERT ('+TSM/tsm/datafile/data_move.285.782738837', '/dev/rhdisk12');
                
                Starting conversion at source at 08-MAY-12
                allocated channel: ORA_DISK_1
                channel ORA_DISK_1: SID=498 device type=DISK
                channel ORA_DISK_1: starting datafile conversion
                input datafile file number=00011 name=+TSM/tsm/datafile/data_move.285.782738837
                converted datafile=/dev/rhdisk12
                channel ORA_DISK_1: datafile conversion compl
                Then when import dumpfile just point the raw disk.
                The raw device must not be created under VG. (i.e you must create each datafile as raw device (LUN)on storage, NOT use LV of AIX).


                Regards,
                Levi Pereira
                • 5. Re:
                  877440
                  ok, I will test this way. Thanks again for your suggestions.

                  Edited by: user9876 on May 10, 2012 6:24 AM