Skip to main content
Hitachi Vantara Knowledge

Creating an erasure coding topology

  1. In the top-level menu of the HCP System Management Console for any system you want to include in the erasure coding topology, select Services Geo-distributed EC.

  2. On the EC Topologies page, click Create Erasure Coding Topology.

    The erasure coding topology creation wizard opens.
  3. Review the information on the wizard Overview page. Then click Next.

  4. On the wizard Name page:

    1. In the Name field, type a name for the erasure coding topology.

      The name must be from one through 64 characters long and can contain any valid UTF‑8 characters, including white space. Erasure coding topology names are not case sensitive. Erasure coding topology names must be unique for each HCP system in the topology. That is, you cannot use the name of a retiring or retired topology as the name for a new topology that will include any of the same systems as the retiring or retired topology. You can reuse the name of a deleted topology.
    2. (Optional) In the Description field, type a description for the erasure coding topology.

      The description can be up to 1,024 characters long and can contain any valid UTF-8 characters, including white space.
  5. Click Next.

  6. On the wizard HCP System Selection page:

    1. In the Number of HCP Systems field, select the number of systems to be included in the erasure coding topology.

    2. If you selected 4, 5, or 6 for the number of systems, for Topology Type, select Ring or Fully connected.

    3. In each numbered field in the HCP Systems section, select an HCP system to be included in the erasure coding topology:

      • For a ring topology, the order of the systems in the numbered fields must correspond to the arrangement of the systems in the topology diagram displayed on the page, with your choice of system as number one.
      • For a fully connected topology, the systems can be in any order in the numbered fields.
    If you don't see all the systems you want to include in the erasure coding topology, check that all required links exist and are healthy.

    In the process of creating the erasure coding topology, HCP may change which system is associated with each number. However, this change in no way affects the topology itself.

  7. Click Next.

  8. On the wizard Link Selection page, for each pair of HCP systems connected by more than one replication link, select the link you want to include in the erasure coding topology.

    For each pair of systems connected by a single link, that link is automatically included in the erasure coding topology. These pairs on not listed on the Link Selection page.
  9. Click Next.

  10. On the wizard Settings page:

    1. For Distribution Method, select Chunk distribution or Full-copy distribution.

    2. In the Minimum Object or Object Part Size for Erasure Coding field, select the minimum size for objects and parts of multipart objects to be erasure coded.

      The options are 4 KB, 16 KB, 32 KB, 64 KB, 128 KB, 256 KB, 512 KB, and 1 MB.
    3. In the Erasure Coding Delay field, type the number of days after ingest that full copies of object or part data should be reduced to chunks.

      Valid values are integers in the range zero through 3,650.
    4. In the Restore Period field, type the number of days that full copies of object or part data should remain on the ingest after being restored from chunks due to a read operation.

      Valid values are integers in the range zero (no restore period) through 180.
  11. Click Next.

  12. On the wizard Review page, review the erasure coding topology configuration.

    • If the erasure coding topology configuration is what you want, click Finish.
    • If the erasure coding topology configuration is not what you want, use the Previous button in the wizard to return to pages on which you want to make corrections. Alternatively, press Cancel to leave the wizard without creating the erasure coding topology.