If you want to manage older versions of an object differently than the current version, rules that use Noncurrent Time as the Reference Time must appear in the ILM policy before rules that apply to the current object version.
An ILM policy for S3 versioned objects might include ILM rules such as the following:
- Keep any older (noncurrent) versions of each object for 2 years, starting from the day the version became noncurrent.Note: The Noncurrent Time rules must appear in the policy before the rules that apply to the current object version. Otherwise, the noncurrent object versions will never be matched by the Noncurrent Time rule.
- At ingest, create three replicated copies and store one copy at each of three data centers. Keep copies of the current object version for 10 years.
When you simulate the example policy, you would expect test objects to be evaluated as follows:
- Any noncurrent object versions would be matched by the first rule. If a noncurrent object version is older than 2 years, it is permanently deleted by ILM (all copies of the noncurrent version removed from the grid).Note: To simulate noncurrent object versions, you must use that version's UUID or CBID. While the object is still current, you can use Object Metadata Lookup to find its UUID and CBID.
- The current object version would be matched by the second rule. When the current object version has been stored for 10 years, the ILM process adds a delete marker as the current version of the object, and it makes the previous object version
noncurrent.
The next time ILM evaluation occurs, this noncurrent version is matched by the first rule. As a result, the copy at DC3 is purged and the two copies at DC1 and DC2 are stored for 2 more years.