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5 Replies Latest reply: Jan 14, 2013 8:40 AM by user738616 RSS

Ensure backup is in a different "zone" location

984175 Newbie
Currently Being Moderated
Hi,

I am investigating using Coherence in-memory data grid in Amazon Web Services.

I want to solve for system resilience and data durability when there is a complete failure in one AWS Availability Zone (AZ). We will have Coherence distributed cache nodes in multiple AZs. Is there a way to guarantee that every object in the cache is stored on at least 2 servers across different availability zones?

Thanks!

Horace
  • 1. Re: Ensure backup is in a different "zone" location
    user639604 Journeyer
    Currently Being Moderated
    I believe if you configure the site-name,rack-name and machine-name properly, Coherence will pick the strongest backup strategy. i.e. store backup partition on different site provide you have site-name configured properly on all nodes.

    http://docs.oracle.com/cd/E24290_01/coh.371/e22837/appendix_operational.htm#BABDAICD

    But I never tested it out, though.

    And you will have to have backup-count greater than 0.
  • 2. Re: Ensure backup is in a different "zone" location
    user639604 Journeyer
    Currently Being Moderated
    Looks like you also have to use Simple Partition Assignment Strategy.

    http://docs.oracle.com/cd/E24290_01/coh.371/e22837/api_dataaffinity.htm#sthref131
  • 3. Re: Ensure backup is in a different "zone" location
    user738616 Pro
    Currently Being Moderated
    Hi,

    The default backing strategy that comes out-of-the-box will not help you. You would need to use the simple partition assignment strategy that will ensure "data safety", by placing primary and backup copies of data on different sites, racks and machines. So if there are multiple sites then primary and backup data will be put on different sites. You need to define the following parameters for JVMs on each AZ:

    -Dtangosol.coherence.site=AZ1 or -Dtangosol.coherence.site=AZ2

    HTH

    Cheers,
    _NJ                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
  • 4. Re: Ensure backup is in a different "zone" location
    DJW Newbie
    Currently Being Moderated
    I believe that using site and rack name will prioritise assignment of backups to alternate site/rack, but will not guarantee it - e.g. if there is asymmetry in capacity between sites, some partitions will be backed up on the same site.
  • 5. Re: Ensure backup is in a different "zone" location
    user738616 Pro
    Currently Being Moderated
    Hi,

    Yes that will happen ..


    HTH

    Cheers,
    _NJ                                                                                                                                                                                                           

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