Creating an ILM rule

ILM rules allow you to manage the placement of object data over time. To create an ILM rule, you use the Create ILM Rule wizard.

1. Select ILM > Rules.
   The ILM Rules page appears, with the stock rule, Make 2 Copies, selected.

   
   
   

2. Click Create.
   Step 1 of the Create ILM Rule wizard appears.
   
   
   
3. Complete Step 1 of the Create ILM Rule wizard.
   1. Enter a unique name for the rule in the Name field.
      You must enter between 1 and 64 characters.
   2. Optionally, enter a short description for the rule in the Description field.
      You should describe the rule's purpose or function so you can recognize the rule later.

      
      
      

   3. From the Tenant Account drop-down list, optionally select the S3 or Swift tenant account to which this rule applies. If this rule applies to all tenants, select Ignore (default).
   4. Use the Bucket Name field to specify the S3 buckets or Swift containers to which this rule applies.
      If matches all is selected (default), the rule applies to all S3 buckets or Swift containers.
   5. Optionally, click Advanced filtering, and specify additional filtering criteria.
      If you do not configure advanced filtering, the rule applies to all objects that match the currently configured criteria (tenant account and bucket).
      See "Using advanced filters in ILM rules" for information about the types of metadata, operators, and metadata values you can specify.
4. Click Next.
   Step 2 of the wizard appears.
   
   
5. For Reference Time, select the time used to calculate the start time for a placement instruction.

   Option	Description
   Ingest Time	The time when the object was ingested.
   Last Access Time	The time when the object was last retrieved (read or viewed). Note: To use this option, updates to Last Access Time must be enabled for the S3 bucket or Swift container.
   Noncurrent Time	The time an object version became noncurrent because a new version was ingested and replaced it as the current version. Note: The Noncurrent Time applies only to S3 objects in versioning-enabled buckets. You can use this option to reduce the storage impact of versioned objects by filtering for noncurrent object versions updated with a new current version or delete marker.
   User Defined Creation Time	A time specified in user-defined metadata.

6. In the Placements section, select a starting time and a duration for the first time period.
   For example, you might want to specify where to store objects for the first year ("day 0 for 365 days"). At least one instruction must start at day 0.
7. If you want to create replicated copies:
   1. Select the number of copies you want to make.
      Note: In general, you should not configure an ILM rule to create only one replicated copy. If the only replicated copy is lost or corrupted, data will be lost.
   2. Select replicated from the copies as drop-down list.
   3. Optionally, click Add Pool and select one or more storage pools.
      If you are specifying more than one storage pool, keep these rules in mind:

      • If you are specifying more than one storage pool and creating n copies, you must add n or more pools. For example, if a rule is configured to make three copies, you must specify three or more storage pools.
      • If the number of copies equals the number of storage pools, one copy of the object is stored in each storage pool.
      • If the number of copies is less than the number of storage pools, the system distributes the copies to keep disk usage among the pools balanced, while ensuring that one copy goes only to one site.
      • If the storage pools overlap (contain the same Storage Nodes), all copies of the object might be saved at only one site. For this reason, do not specify the default storage pool (All Storage Nodes) and another storage pool.

      
      
      
   4. If you are using only a single storage pool, specify a temporary storage pool.
      
      
      

      Specifying a temporary storage pool is optional, but recommended. If the preferred storage pool is unavailable, a copy is made in the temporary storage pool. As soon as the preferred storage pool becomes available, a copy is made in the preferred storage pool, and the copy in the temporary storage pool is deleted.

      Attention: Failing to specify a temporary storage pool puts object data at risk if the preferred pool is unavailable.
8. If you want to create an erasure-coded copy:
   1. Select erasure coded from the copies as drop-down list.
      The number of copies changes to 1.
   2. Select the storage location.
      The storage locations for an erasure-coded copy include the name of the storage pool, followed by the name of the Erasure Coding profile.

      
      
      

9. Optionally, click the plus icons to add placement instructions that specify different time periods or create additional copies at different locations.
10. Click Refresh to update the Retention Diagram and to confirm your placement instructions.
    Each line in the diagram represents a placement instruction and shows where and when object copies will be placed. The type of copy is represented by one of the following icons:

    • One or more replicated copies
    • Erasure coded copy
    In this example, replicated copies will be saved to three storage pools (DC1, DC2, and DC3) for one year. Then, an erasure-coded copy will be saved forever, using the Erasure Coding profile associated with the All Storage Nodes storage pool.
    
    

    Attention: When adding a rule that makes an erasure-coded copy to the ILM policy, you must ensure that the policy has at least one rule that filters by Object Size. Due to the overhead of managing the number of fragments associated with an erasure coded copy, do not erasure code objects smaller than 200 KB.
11. Click Save.
    The ILM rule is saved. The rule does not become active until it is added to an ILM policy and that policy is activated.