Topic
3 replies Latest Post - ‏2013-05-29T17:22:13Z by AndersLorensen
Cocas83
Cocas83
5 Posts
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Pinned topic Is it possible to expand a Pool in V7000?

‏2013-05-27T23:48:41Z |

Hello

I have a V7000, one Pool configured with two mdisks (raid5) and a ssd mdisk.

We 've installed four new sas disks of identical specs,and when we configure the new storage and select to expand an existing pool, no pool shos on the windows and the legend "the are currently no poolson the system that satisfy the drive class and Raid preset"

Any clues?

By the way, the new capacity was configured as raid 5 also. Easy tier is activated on the Pool

  • AndersLorensen
    AndersLorensen
    156 Posts
    ACCEPTED ANSWER

    Re: Is it possible to expand a Pool in V7000?

    ‏2013-05-28T07:37:09Z  in response to Cocas83

    All MDISKs of a pool should have the same performance chararistics. If your new raid5 has less physical disks than the existing disks, the GUI might now allow you to add it to the pool.

    You can do it from the CLI if you really want to add it.

    Depending on free space in the pool, you might want to increase the existing 2 raids with 2 disks each. To do that, you have to remove 1 mdisk, create a new mdisk with 2 more disks in, then do the same to the other existing mdisk.

    Optimal/Best practice is 7-9 physical disks in a raid5 for each mdisk.

     

    --

    Anders

    • cocas24
      cocas24
      1 Post
      ACCEPTED ANSWER

      Re: Is it possible to expand a Pool in V7000?

      ‏2013-05-28T14:48:23Z  in response to AndersLorensen

      Hello Anders,

      So you are saying that the V7000 is detecting that the new mdisk of 4 HDD SAS 600GB is no giving the same performance that the previously created mdisk of 6x600GB SAS? If I added anyway via CLI, don`t the Tier 0 SSD take care of the "performance differences" of the mdisks?

      If I remove on mdisk, and then create a new one with eg. 8HDD, I would face the same problema when I want to add that mdisk to the Pool right?

      I thin is a risky operation, since I have to delete a mdisk, migrate all tha data to the other mdisk, create a new mdisk, add it to the pool, and repeat all for the other mdisk.

      That sould be a dynamic operation.....thumb down for the V7000

      • AndersLorensen
        AndersLorensen
        156 Posts
        ACCEPTED ANSWER

        Re: Is it possible to expand a Pool in V7000?

        ‏2013-05-29T17:22:13Z  in response to cocas24

        The SSD's wont remove the differences, but it will make it better. Whenever its the gui that detects the performance difference I dont know. I've never had the problem. But I've always used the "capacity optimized" option when creating stuff. The "Performance optimized" option makes all mdisks identical.

        Performance wise, I'd go with 2 raids of 8 disks in your situation, if you have the capacity free to do it.

        And yeah, the fact that you cannot add a disk to a raidset on the storwize have annoyed me alot as well. Same goes for changing raid level.

        If you set the Extend size very low when you created the pool, that might be a reason for you to not be able to add the mdisk as well. (Extend size put limits on max pool size)

        --

        Anders