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Cloud Tiering Appliance (CTA) enables the ability to tier data from Dell Unity to another location based on user-configured policies. An example of this includes moving any files that are larger than 50 MB and has not been accessed in 30 days to the cloud. After a file is moved off the primary storage, an 8 KB stub is left which points to the actual location of the data. Any requests to read the data that has been moved can be configured as a pass-through, partial recall, or full recall from the cloud. From the end user point of view, this process is seamless since the stub resembles the actual file and the data continues to be accessible on demand. Archived files are marked with the offline file icon in Windows Explorer, so they can be easily identified.
The CTA interface is shown in the figure below.
With OE version 4.2 and CTA version 12 SP1, the CTA file migration feature is supported. This feature can be used to migrate file data from VNX to Dell Unity. The destination file system must have multiprotocol-enabled and needs enough capacity to hold the entire dataset from the source. For example, if deduplication and compression are enabled on the source file system, the destination file system is rehydrated so that must be considered.
Starting with OE version 4.2 and CTA version 12, support for tiering of block snapshots to the cloud is available. This provides the ability to archive and restore block snapshots to and from the cloud. This works with both LUNs and consistency groups and leverages iSCSI connectivity between CTA and the Dell Unity system. Like file tiering, tiering of block snapshots is also based on policies and schedules created by the administrator. Once a snapshot is archived to the cloud, it can be deleted off the Dell Unity system to free up storage. Snapshots can also be restored from the cloud on to a new storage resource on the Dell Unity system.
Starting with OE version 4.1 and CTA version 11, CTA support for Dell Unity is available. When using CTA with Dell Unity as the source, only tiering to Virtustream, Azure, and S3 cloud repositories are supported. When tiering to a cloud repository, CTA can also leverage compression and/or encryption. Although CTA can tier other Dell storage, this is not supported when Dell Unity is configured as the source.
There are two deployment options: CTA and CTA-VE (Virtual Edition). CTA comes as an ISO image that can be installed on a physical server. There is no option to purchase a physical CTA appliance from Dell so a customer-supplied server must be used. CTA/VE is installed on ESXi and runs as a VM. Both options include CTA-HA (High Availability) to provide redundancy for recall operations. Recall requests can also be configured to use both CTA and CTA-HA in a round-robin fashion to load balancing.
The minimum requirements for each are:
Once CTA is deployed and configured, browse Configuration à Common API Settings. Provide the Dell Unity management credentials and set a DHSM password. When a Dell Unity system is added as a source file server, this information is used to configure DHSM automatically on the NAS server. Alternatively, you can still configure it manually by enabling DHSM and setting a password under NAS server Properties à Protection & Events à DHSM. If multiple Dell Unity systems are configured on a single CTA, the Dell Unity management credentials and DHSM password must be same across all the Dell Unity systems.
In CTA, add Dell Unity as a source file server by providing details such as NetBIOS name, Dell Unity management IP, authentication details, and the DNS name of CTA. To configure a cloud repository, enable the Cloud Callback Daemon and provide information such as the endpoint, access key, secret key, and bucket. Verify connectivity for both Dell Unity and the cloud repository to ensure the configuration is correct. Then, create policies to tier data depending on specific attributes and schedules to run these jobs automatically.
For more information about CTA, reference the Dell Unity: Cloud Tiering Appliance (CTA) white paper and Cloud Tiering Appliance: User Guide on Dell Technologies Info Hub.