Configuring the WORM Storage Mode on Cloud Storage

Cloud storage vendors can support WORM functionality using one of the following methods:

  • Vendors that support a WORM policy at the bucket / container level

    To achieve WORM functionality for such vendors, the WORM policy has to be enabled at the bucket /container level in the Cloud storage vendor's interface.

    For example, vendors like Amazon Glacier using Vault Lock Policy, Amazon S3 Object lock, Nutanix Buckets (S3 Compatible Storage), EMC ECS Storage and Microsoft Azure using Immutable Blob Storage functionality, Google Cloud Storage, can configure the WORM policy.

    For non-deduplicated data, as these WORM policies are usually based on number of days or months of retention from the time the data was written on the storage, make sure that the retention settings established at the Storage Policy Copy is higher than or equal to the bucket level retention established in the cloud. Otherwise some of the pruning operations might fail due to the WORM retention setting on the storage side. For more information on establishing the retention rules, see Setting Up the Basic Retention Rule.

    For deduplicated (DDB) data, disable micro-pruning. Seal the DDB and wait for the lock period on the WORM policies to prune the DDB data. For example, if the lock period is 30 days, wait for 30 days after sealing the DDB to prune the DDB data. See the following topics for additional information on these operations:

  • Vendors that support retention at the object level

    To achieve WORM functionality on cloud storage vendors who support retention at object level, you can enable the Mark Archive files as Read-Only option from the Cloud Library Properties dialog box. (For more information on marking the archive files as read-only, see Configuring Files as Read-Only.)

    For example, vendors like Hitachi and Caringo storage support this function.


  • WORM functionality can be enabled on existing storage targets.
  • Once applied, the WORM functionality is irreversible.
  • May incur additional cloud library costs.


WORM storage mode is supported on cloud storage libraries that support the WORM mode. Refer to the appropriate cloud storage vendor documentation to verify whether the WORM mode is supported.

Last modified: 3/23/2021 4:54:53 PM