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CloudPools Operation Workflows

Jason He Sep 30, 2026
CloudPools Operation Workflows

The Dell PowerScale CloudPools feature of OneFS allows tiering cold or infrequently accessed data to move to lower-cost cloud storage. CloudPools extends the PowerScale namespace to the private cloud, or the public cloud. For CloudPools supported cloud providers, see the CloudPools Supported Cloud Providers blog.

This blog focuses on the following CloudPools operation workflows:

  • Archive
  • Recall
  • Read
  • Update

Archive

The archive operation is the CloudPools process of moving file data from the local PowerScale cluster to cloud storage. Files are archived either using the SmartPools Job or from the command line. The CloudPools archive process can be paused or resumed.

The following figure shows the workflow of the CloudPools archive.

 This figure illustrates the workflow of the CloudPools archive: 1. A file matches a file pool policy. 2. The file data is split into chunks Cloud Data Object (CDO). 3. The chunks are sent from the PowerScale cluster to cloud. 4. The file is truncated into a SmartLink file and a Cloud Metadata Object (CMO) is written to cloud.

Figure 1.  Archive workflow

More workflow details include:

  • The file pool policy in Step 1 specifies a cloud target and cloud-specific parameters. Policy examples include:
  • Encryption: CloudPools provides an option to encrypt data before the data is sent to the cloud storage. It uses the PowerScale key management module for data encryption and uses AES-256 as the encryption algorithm. The benefit of encryption is that only encrypted data is being sent over the network.
  • Compression: CloudPools provides an option to compress data before the data is sent to the cloud storage. It implements block-level compression using the zlib compression library. CloudPools does not compress data that is already compressed.
  • Local data cache: Caching is used to support local reading and writing of SmartLink files. To optimize performance, it reduces bandwidth costs by eliminating repeated fetching of file data for repeated reads and writes. The data cache is used for temporarily caching file data from the cloud storage on PowerScale disk storage for files that have been moved off cluster by CloudPools.
  • Data retention: Data retention is a concept used to determine how long to keep cloud objects on the cloud storage.
  • When chunks are sent from the PowerScale cluster to cloud in Step 3, a checksum is applied for each chunk to ensure data integrity.

Recall

The recall operation is the CloudPools process of reversing the archive process. It replaces the SmartLink file by restoring the original file data on the PowerScale cluster and removing the cloud objects in cloud. The recall process can only be performed using the command line. The CloudPools recall process can be paused or resumed.

The following figure shows the workflow of CloudPools recall. 

This figure illustrates the workflow of the CloudPools recall: 1. OneFS retrieves the CDOs from cloud to the PowerScale cluster. 2. The SmartLink file is replaced by restoring the original file data. 3. The cloud objects are removed in cloud asynchronously if the data retention period has expired.

Figure 2.  Recall workflow

Read

The read operation is the CloudPools process of client data access, known as inline access. When a client opens a file for read, the blocks are added to the cache in the associated SmartLink file by default. The cache can be disabled by setting the accessibility in the file pool policy for CloudPools. The accessibility setting is used to specify how data is cached in SmartLink files when a user or application accesses a SmartLink file on the PowerScale cluster. Values are cached (default) and no cache.

The following figure shows the workflow of CloudPools read by default. 

This figure illustrates the workflow of the CloudPools read: 1. Client accesses the file through the SmartLink file. 2. OneFS retrieves CDOs from cloud to the local cache on the PowerScale cluster. 3. FIle data is sent to the client from the local cache on the PowerScale cluster. 4. OneFS purges expired cache information for the SmartLink file.

Figure 3.  Read workflow

Starting from OneFS 9.1.0.0, cloud object cache is introduced to enhance CloudPools functions for communicating with cloud. In Step 1, OneFS looks for data in the object cache first and OneFS retrieves data from the object cache if the data is already in the object cache. Cloud object cache reduces the number of requests to cloud when reading a file.

Prior to OneFS 9.1.0.0, in Step 1, OneFS looks for data in the local data cache first. It moves to Step 3 if the data is already in the local data cache.

Note: Cloud object cache is per node. Each node maintains its own object cache on the cluster. 

Update

The update operation is the CloudPools process that occurs when clients update data. When clients change to a SmartLink file, CloudPools first writes the changes in the data local cache and then periodically sends the updated file data to cloud. The space used by the cache is temporary and configurable.

The following figure shows the workflow of CloudPools update. 

This figure illustrates the workflow of the CloudPools update: 1. The client accesses the file through the SmartLink file. 2. OneFS retrieves CDOs from cloud, putting the file data in the local cache. 3. The client updates the file and those changes are stored in the local cache. 4. OneFS sends the updated file data from the local cache to cloud. 5. OneFS purges expired cache information for the SmartLink file.

Figure 4.  Update workflow

Thank you for taking the time to read this blog, and congratulations on gaining a clear understanding of how the OneFS CloudPools operation works!

Author: Jason He, Principal Engineering Technologist

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