Lifecycles

Azure Blob Storage offers the ability to manage data lifecycles so that blobs are moved down through colder tiers and eventually expired as it gets older. With lifecycle management, you can:

Move blobs from cool to hot when accessed
Move blobs into colder tiers if they are not accessed for a while
Delete blobs after a certain amount of time
Apply rules to whole accounts, containers or sets of blobs using name prefixes or tags

Policies

A policy is a collection of rules, which in turn is a collection of filters and actions to apply to blobs in your storage.

Rules

{
  "rules": [
    {
      "name": "rule1",
      "enabled": true,
      "type": "Lifecycle",
      "definition": {...}
    },
    {
      "name": "rule2",
      "type": "Lifecycle",
      "definition": {...}
    }
  ]
}

Parameter name	Parameter type	Notes	Required
`name`	String	A rule name can include up to 256 alphanumeric characters. Rule name is case-sensitive. It must be unique within a policy.	True
`enabled`	Boolean	An optional boolean to allow a rule to be temporarily disabled. Default value is true.	False
`type`	An enum value	The current valid type is Lifecycle.	True
`definition`	An object that defines the lifecycle rule	Each definition is made up of a filter set and an action set.	True

Actions and filters

Each rule definition contains a list of actions and a list of filters.

{
  "rules": [
	// rule
	{
      "enabled": true,
      "name": "sample-rule",
      "type": "Lifecycle",
      "definition": {
	    // actions
        "actions": {
          "baseBlob": {
            "tierToCool": {
              "daysAfterModificationGreaterThan": 30
            },
            "tierToArchive": {
              "daysAfterModificationGreaterThan": 90,
              "daysAfterLastTierChangeGreaterThan": 7
            },
            "delete": {
              "daysAfterModificationGreaterThan": 2555
            }
          },
          "snapshot": {
            "delete": {
              "daysAfterCreationGreaterThan": 90
            }
          }
        },
        // filters
        "filters": {
          "blobTypes": [
            "blockBlob"
          ],
          "prefixMatch": [
            "sample-container/blob1"
          ]
        }
      }
    }
  ]
}

Filters

Filter name	Type	Is Required
blobTypes	An array of predefined enum values.	Yes
prefixMatch	An array of strings for prefixes to be match. Each rule can define up to 10 prefixes. A prefix string must start with a container name.	No
blobIndexMatch	An array of dictionary values consisting of blob index tag key and value conditions to be matched. Each rule can define up to 10 blob index tag condition.	No

Actions

Action	Current Version	Snapshot	Previous Versions
tierToCool	Supported for `blockBlob`	Supported	Supported
tierToCold	Supported for `blockBlob`	Supported	Supported
enableAutoTierToHotFromCool	Supported for `blockBlob`	Not supported	Not supported
tierToArchive	Supported for `blockBlob`	Supported	Supported
delete	Supported for `blockBlob` and `appendBlob`	Supported	Supported

With conditions:

Action run condition	Condition value	Description
daysAfterModificationGreaterThan	Integer value indicating the age in days	The condition for base blob actions
daysAfterCreationGreaterThan	Integer value indicating the age in days	The condition for blob snapshot actions
daysAfterLastAccessTimeGreaterThan	Integer value indicating the age in days	The condition for a current version of a blob when access tracking is enabled
daysAfterLastTierChangeGreaterThan	Integer value indicating the age in days after last blob tier change time	The minimum duration in days that a rehydrated blob is kept in hot, cool, or cold tiers before being returned to the archive tier. This condition applies only to `tierToArchive` actions.

Adding policies

Lifecycle policies can be added in Azure portal either through "list view" or "code view".

Storage Account > Data management > Lifecycle management > Code view (tab)

{
  "rules": [
    {
      "enabled": true,
      "name": "move-to-cool",
      "type": "Lifecycle",
      "definition": {
        "actions": {
          "baseBlob": {
            "tierToCool": {
              "daysAfterModificationGreaterThan": 30
            }
          }
        },
        "filters": {
          "blobTypes": [
            "blockBlob"
          ],
          "prefixMatch": [
            "sample-container/log"
          ]
        }
      }
    }
  ]
}

You can also add policies via the Azure CLI. The CLI accepts a full JSON document of rules to replace to current rules. Partial updates are not supported.

az storage account management-policy create \
   --account-name <storage-account> \
   --policy @policy.json \
   --resource-group <resource-group>