9 Replies Latest reply: Jan 13, 2014 8:21 AM by user12037272 RSS

ASM with two SAN's.

user6644245 Newbie
Currently Being Moderated

We're in a re-architecturing stage of our databases and just recently we've experienced the 4th SAN blip since a SAN has existed in our shop.

 

We're contemplating having two different SAN's (maybe even from different vendors) to remove the single point of failure. Yes, our SAN was sold as a "dual everything" and could never break SAN. BUT it still shares the same firmware which of course after a firmware upgrade blew it's brains when it was attempting a fail over leaving us with a "brown outage" (half the systems down, a quarter in a funny state and a quarter humming along). Of the 4 outages, 3 different brands of SAN's.

 

I've read some stuff on ASM but am not finding a clear answer, can I mirror all flow of data to our Oracle databases to the two different SAN's so that if SAN 1 breaks, SAN 2 takes over with no loss of service? Or would I still need some Dataguard or something to make this work?

 

Thanks for any response in advance.

 

Paul.

  • 1. Re: ASM with two SAN's.
    JavierFranciscoRuiz Explorer
    Currently Being Moderated

    Yes you can do this with ASM setup the diskgroup as normal redundancy. Explain you would create two failgroups one call A and the other call B. In failgroup A you would put all the disk/LUNS from SAN A and in failgroup B you would put all disk/LUNS from SAN B.

     

    We had the same issue with a SAN outage so we converted our ASM disk group to normal redundancy from cross cabinet outage issues.

     

    If you send me your email I can send you a document I created during our testing so you can get more understand of the possible configuration.

  • 2. Re: ASM with two SAN's.
    Dude! Guru
    Currently Being Moderated

    For ASM it does not matter what technology is behind your devices in terms of providing data redundancy. If you configure ASM with normal or high redundancy, ASM provides data redundancy between disk failure groups. ASM does however not mirror devices, and uses file extents (AU units) distributed on available free space of disk failure groups.

     

    How you configure your ASM disk groups is up to you. By default, every device is its own failure group, but it it can be configured. If you have different physical paths to your devices, you might want to combine separate ASM disk groups by controller or storage paths for additional hardware fail-over.

     

    ASM provides performance and redundancy from the point of data storage devices. It does not provide redundancy for your Oracle database instance or services. Oracle Dataguard provides service and data availability by the means of synchronizing data between a primary and standby database.

  • 3. Re: ASM with two SAN's.
    user6644245 Newbie
    Currently Being Moderated

    Thanks Javier,

     

    Email address: paul_klassen@umanitoba.ca

     

    Paul.

     

  • 4. Re: ASM with two SAN's.
    JavierFranciscoRuiz Explorer
    Currently Being Moderated

    I sent you the documentation I created thanks.

  • 5. Re: ASM with two SAN's.
    BillyVerreynne Oracle ACE
    Currently Being Moderated

    user6644245 wrote:

     

    I've read some stuff on ASM but am not finding a clear answer, can I mirror all flow of data to our Oracle databases to the two different SAN's so that if SAN 1 breaks, SAN 2 takes over with no loss of service? Or would I still need some Dataguard or something to make this work?

    I have a RAC that runs 2 storage arrays as mirrors via ASM.

     

    Works great. Have had complete chassis failure of the one array, without the database being aware of it. Architecturally, whether it is an actual SAN, or a storage array, is immaterial to ASM. This particular I/O fabric layer is Infiniband and not Fibre Channel, but that does not impact ASM at all either the one way or the other.

     

    Keys issues IMO are

    • you still need full redundancy per SAN/storage array with multiple I/O paths via redundant swicthes
    • you need similar I/O performance from both SANs/storage arrays
  • 6. Re: ASM with two SAN's.
    user6644245 Newbie
    Currently Being Moderated

    Thanks,

     

    This was exactly what I was looking for.

     

    Paul.

  • 7. Re: ASM with two SAN's.
    Egigliesi Newbie
    Currently Being Moderated

    Hi JavierFranciscoRuiz

    I'm interested about the ASM and two SAN implementation.

    Could I have your documentation?

    Can I get it by FTP or dropbox?

    Thanks a lot.

  • 8. Re: ASM with two SAN's.
    user6644245 Newbie
    Currently Being Moderated

    I still have it, I'll just need your email so I can send it.

  • 9. Re: ASM with two SAN's.
    user12037272 Explorer
    Currently Being Moderated

    Hello

     

     

    I'm very interested in Javier's documentation, can I have it?

     

    tks

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