PowerScale CloudPools allows tiering cold or infrequently accessed data to lower-cost cloud storage. After file data has been archived to the cloud storage, the file is truncated to an 8 KB file. The 8 KB file is called a SmartLink file. CloudPools allows applications and users to seamlessly retain access to data through the same network path and protocols, regardless of where the file data physically resides.

OneFS NDMP is CloudPools-aware and supports three backup methods for CloudPools:

• Combo copy backup: Combo copy backup is introduced in OneFS 8.2.0. This option is used to back up files as SmartLink files with file data. Files can be restored as regular files or SmartLink files. This option is the default setting in OneFS 8.2.0 and higher.
• Deep copy backup: This option is used to back up files as regular files or unarchived files. Files can only be restored as regular files.
• Shallow copy backup: This option is used to back up files as SmartLink files without file data. Files can only be restored as SmartLink files. This option is the default setting before OneFS 8.2.0.

Note: Deep copy and combo copy backups retrieve file data from the cloud. The file data is not cached or stored on disks during the backups. Retrieving file data from the cloud may incur charges from cloud vendors, and the backup performance may degrade. Shallow copy backup backs up SmartLink files without file data and improves the backup performance.

OneFS NDMP provides the following capabilities with CloudPools:

• Restoring SmartLink files or regular files to the same PowerScale cluster.
• Restoring SmartLink files or regular files to another PowerScale cluster. After SmartLink files are restored and detected on the target cluster, OneFS automatically configures the cloud storage account, CloudPools, and the file pool policy matching the source cluster configuration.
• Backing up version information with each SmartLink file and restoring the SmartLink file after verifying the version compatibility on the target PowerScale cluster.

Note: NDMP backs up the relevant information along with SmartLink files, such as CloudPools version information, account information, encryption keys that are associated with the SmartLink file. NDMP backs up the cache of SmartLink files before OneFS 8.2.0. NDMP does not back up the cache of SmartLink files in OneFS 8.2.0 and later.

The following table shows the NDMP supported restore use cases when running a different version of CloudPools on the source and target PowerScale clusters.

Table 5.      NDMP supported restore use cases with a different version of CloudPools

You can specify how SmartLink files are backed up and restored by setting the NDMP environment variables BACKUP_OPTIONS and RESTORE_OPTIONS. For details about how to set and manage NDMP environment variables, see the PowerScale OneFS CLI Administrator Guide.

CloudPools 2.0 (SmartLink files version) is backward compatible with CloudPools 1.0. However, CloudPools 1.0 is incompatible with CloudPools 2.0. The following table shows the NDMP supported backup options and restore options with CloudPools.

Table 6.      NDMP supported backup options and restore options with CloudPools

We recommend using the combo copy backup option. When the combo copy backup option is used for backup, you can use the shallow copy, or deep copy restore options to recover SmartLink files. For the NDMP backup and restore options, the considerations include the following:

• If you do not specify any backup option, NDMP backs up SmartLink files using the combo copy backup option by default.
• If you do not specify any restore operation, NDMP restores SmartLink files from combo copy backups using the combo copy restore option by default. For the combo copy restore, you can use shallow copy restore option or deep copy restore option by setting the RESTORE_OPTIONS environment variable.
• If the version check operation on the target cluster is successful, the shallow copy restore operation restores SmartLink files as SmartLink files on the target cluster.
• If the version check operation on the target cluster fails, the deep copy restore operation forces the recovery of the SmartLink files as regular files on the target cluster.

OneFS allows users to update the file data through SmartLink files and writes back the updated data to the cloud storage. Multiple versions of SmartLink files can be backed up to tapes using NDMP, and multiple versions of cloud data objects are protected on the cloud under the data retention setting. You can restore a specific version of a SmartLink file from tapes to a PowerScale cluster and continue to access to the restored SmartLink files.

Data retention is a concept used to determine how long to keep cloud objects on the cloud storage. There are the following three different retention periods in CloudPools setting:

• Cloud data retention period: This option is used to specify the length of time cloud objects are retained after the files have been fully recalled or deleted. The default value is one week.
• Incremental backup retention period for NDMP incremental backup and SyncIQ: This option is used to specify the length of time that CloudPools retains cloud objects referenced by a SmartLink file. Also, SyncIQ replicates the SmartLink file or NDMP backs up the SmartLink file using an incremental NDMP backup. The default value is five years.
• Full backup retention period for NDMP only: This option is used to specify the length of time that OneFS retains cloud data referenced by a SmartLink file. Also, NDMP backs up the SmartLink file using a full NDMP backup. The default value is five years.

If more than one period applies to a file, the longest period is applied. CloudPools checks the retention periods of SmartLink files and ensure that SmartLink files are valid. CloudPools disallows restoring invalid SmartLink files. When restoring SmartLink files, the retention period must be set appropriately to ensure that SmartLink files are valid. If the retention time of a SmartLink file is past the restore time, CloudPools prevents NDMP from restoring that SmartLink file.

Note: Do not delete a cloud storage account that is in use by archived files. NDMP backup and restore of SmartLink files will fail when the cloud storage account has been deleted.