Recalling files from the cloud storage tier

This topic provides a brief description on how to recall files from the cloud storage tier by using Transparent cloud tiering.

You can trigger recall of files from the cloud storage tier either transparently or manually. Transparent recall is based on the policies that are applied on a file system. Data is automatically moved from the cloud storage tier to the system pool when the system pool reaches a certain threshold level. A file can be automatically recalled from the cloud storage tier based on some characteristics of the file such as age, size, last access time, path. Alternatively, the user can manually recall specific files or file sets. For more information on policy-based recall, see Applying a policy on a Transparent cloud tiering node.

You can enable or disable transparent recall for a container when a container pair set is created. For more information, see Binding your file system or fileset to the Cloud service by creating a container pair set.

Note: Like recalls in IBM Spectrum Archive and IBM Storage Protect for Space Management, Transparent cloud tiering recall would be filling the file with uncompressed data and the user would need to re-compress it by using mmrestripefs or mmrestripefile if so desired. Since we are positioning compression feature for cold data currently, the fact of a file being recalled means the file is no longer cold and leaving the file uncompressed would allow better performance for active files.

To manually trigger recall of the file file1, issue this command:

mmcloudgateway files recall file1

The state of the file becomes Co-resident after it is successfully recalled. If the file that has been recalled no longer needs to be kept in the cloud tier it can be deleted. For more information on deleting a file in the co-resident state, see Cleaning up files transferred to the cloud storage tier.

For more information on manually recalling files, see mmcloudgateway command command.