Re: Volume Tiering

Mohammed Rafi K C <rkavunga@xxxxxxxxxx> · Mon, 02 May 2016 17:45:03 +0530



    comments are inline.

    
    On 05/02/2016 05:06 PM, Lindsay
      Mathieson wrote:

    
      On 2/05/2016 2:29 PM, Mohammed Rafi K
        C wrote:

      
      Hi
        Lindsay,

        
        Volume level data tiering was made fully supported in latest 3.7
        releases, though an active effort is still going on to increase
        the small file performance. You can find a starting point
        through the blog post by Dan [1].

        
        Let me know if you have any additional questions.

        
        [1]  : http://blog.gluster.org/2016/03/automated-tiering-in-gluster/
      

      Thanks Mohammed, an informative read. When things have settled
        down a bit at work I'l setup a test volume to attach tiers to.
        Ironically, now we've migrated the production env to gluster, my
        ability to test is lessened  - can't tweak it arbitrarily now :)
    
    
    I understand that, and I know the effort you put to achieve it :). I
    really appreciate it .

    
    In fact , tiering is for an eventual performance boost, so no hurry,
    we can start eventually ;).  just kidding. :)

    
      Some questions:
      - Does the hot tier replication level have to match the cold
        tier? i.e brick for brick?
    
    Nop. To understand it easily, You can consider hot tier and cold
    tier as a separate volume which clubbed together as a single volume.
    Which means you can create a different configuration in both tiers.
    In fact there are some volume configuration we are not supporting on
    hot tier, like disperse. There is no point of configuring a high
    performance ssd for ec, right ? 

    
    You can use supported volume configuration in any magnitude.

    
      - I presume the files are promoted across all bricks. i.e you
        can't have different files promoted per brick.
    
    
    I didn't get your question correctly. But I will try to answer
    generically . File movement happens from one tier to another tier,
    as I mentioned earlier, you can consider this as moving one file
    from one volume to another volume. 

    
    As an example, let us assume, you are moving a file from hot tier
    (replica configuration) to a cold tier which is a distributed
    disperse configuration, then the file will be hashed to any of the
    distribute set, then the file will be created with ec meta data
    (data and parity).

    
    I'm  not sure, I made it more complicated ;).

    
      - With sharded volumes its the individual shards that are
        promoted?
    
    
    Since shardes are stored as a separate files in backend, the
    movement will be based on shardes.

    
    Please feel free to ask if you have any other question of if you
    need more clarification on given answers.

    
    Regards

    Rafi KC

    
      thanks,

      
      -- 
Lindsay Mathieson
    
    
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