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8 Replies Latest reply: Jun 27, 2012 12:57 PM by tychos RSS

DBFS Exadata

936749 Newbie
Currently Being Moderated
Hi,
We have several databases that we're going to migrate to Exadata. All of the databases exports are too large to fit on the filesystem on Exadata. As I understand we need to use DBFS to mount the ASM volum to our filesystem (Is this correct?).
In note 1054431.1 it assumes the following:
3.In the procedures listed in this note, both Solaris and Linux database servers are assumed to have user equivalence for root and the DBFS respository database (typically "oracle") users. Each of those users is assumed to have a dbs_group file in their $HOME directory that contains a list of cluster hostnames. The dcli utility is assumed to be available on both Solaris and Linux database nodes.

As I'm new to Exadata(used to single node database and filesystem) I have no idea what the dbs_group file is and how I can create it.
All I know is that this file is not in Oracle / Root home directories.

Can anyone please advice?
Regards
933746

Edited by: 933746 on Jun 26, 2012 9:20 AM
  • 1. Re: DBFS Exadata
    933318 Newbie
    Currently Being Moderated
    1. What storage servers is your current systems running, if its just an NFS,
    then all you need to do is jus mount them on exadata servers and use RMAN and migrate to ASM on exadata.

    2, If you are already using a ASM. Then you have two options.

    1. Use a RMAN active duplicate( This will be very slow with I/O being a big bottle neck.
    2. Take a backup on NFS filesystem and then use RMAN duplicate.
  • 2. Re: DBFS Exadata
    936749 Newbie
    Currently Being Moderated
    930315 wrote:
    1. What storage servers is your current systems running, if its just an NFS,
    then all you need to do is jus mount them on exadata servers and use RMAN and migrate to ASM on exadata.

    2, If you are already using a ASM. Then you have two options.

    1. Use a RMAN active duplicate( This will be very slow with I/O being a big bottle neck.
    2. Take a backup on NFS filesystem and then use RMAN duplicate.
    Hi and thanks for the answer.
    We'll I'm going to do a logical export to a file on local system and then move it with FTP. We're looking into doing this by a DB link so we don't need to export to filesystem at all but not there yet. So i'd like to use some of the Exadata's ASM volum as a filesystem to be able to transfere the 500GB .dmp files to Exadata database server.
    I understand that following the note 1054431.1 is how I can end up with DBFS which use some of the ASM storage and not just the physical disk on the database node.

    To do this I need to have dbs_group files configured on both Oracle user home director and roots.
    Regards

    Edited by: 933746 on Jun 26, 2012 9:49 AM
  • 3. Re: DBFS Exadata
    gsalem Explorer
    Currently Being Moderated
    If you use expdp, you can put the files directly in ASM, and import from there, without using dbfs.
    Now, if you have to use exp, you can't go through ASM. You'll need to use a dbfs, or as previously suggested an NFS mount somewhere.
    For the dbs_group file, you should have it on you exadata system, it is there when the machine is configured by ACS.
  • 4. Re: DBFS Exadata
    UweHesse Expert
    Currently Being Moderated
    DBFS in Exadata is for flat files in the first place. Files you process with External Tables resp. SQL*Loader, that is.
    Data Pump dumpfiles can (and should) be placed on ASM diskgroups directly - no need for DBFS here.

    Kind regards
    Uwe Hesse

    "Don't believe it, test it!"
    http://uhesse.com
  • 5. Re: DBFS Exadata
    936749 Newbie
    Currently Being Moderated
    Uwe Hesse wrote:
    DBFS in Exadata is for flat files in the first place. Files you process with External Tables resp. SQL*Loader, that is.
    Data Pump dumpfiles can (and should) be placed on ASM diskgroups directly - no need for DBFS here.

    Kind regards
    Uwe Hesse

    "Don't believe it, test it!"
    http://uhesse.com
    Thanks!
    Can you please help with some additional details as there is clearly something I do not understand here. I export the database from source database server with expdp. I end up with a file how can this be moved into ASM diskgroup directly? I was planning to use SCP from source server against Exadata.
    If we could skip DBFS I'd be really happy so nothing would be better.
    Regards
    933746
  • 6. Re: DBFS Exadata
    933318 Newbie
    Currently Being Moderated
    Why do you want to use the space of Exadata ASM to store your dump file, using DBFS.

    Once the import is done, this will be a waste of resource for you. So better to have it on external disks.

    If you plan to intend impdp...then you can do it from anywhere...Just configure the sourece tnsnames.ora with the target tns entry

    impdp user/passwd@target.
  • 7. Re: DBFS Exadata
    UweHesse Expert
    Currently Being Moderated
    One way to do that is described here:
    http://docs.oracle.com/cd/E11882_01/server.112/e22490/dp_export.htm#BEHIJGJA

    You need to create a directory on the target location (inside an ASM diskgroup) beforehand.

    Another way to move any file between two Oracle Databases (with or without ASM) is DBMS_FILE_TRANSFER, but you don't need that for Data Pump dumpfiles.

    Kind regards
    Uwe Hesse

    "Don't believe it, test it!"
    http://uhesse.com
  • 8. Re: DBFS Exadata
    tychos Expert
    Currently Being Moderated
    Hi,
    Can you give some details what the issue is with this approach?
    We're looking into doing this by a DB link so we don't need to export to filesystem at all but not there yet.
    We use datapump over a db link so we do not need an intermediate file system and have a 1 step approach.
    Are you on 9i or lower on the source system?
    Regards,
    Tycho

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