Archiving data from mainframe storage systems has been traditionally limited to an on premises physical or virtual tape tier. However, IBM has overcome that limitation with the introduction of Transparent Cloud Tiering (TCT) software that runs on DS8880 storage systems for z Systems. TCT widens the archiving storage targets to cloud environments and that brings the benefits of hybrid cloud with it, such as creating more and better options for managing both capital and operating expenses.


Why IBM is doing this reflects the fact that data tends to change in value over time. Keeping older data on primary production storage is expensive not only in terms of storage costs, but also in terms of the resources needed to manage that data (such as for backup and disaster recovery). The solution is to archive less frequently used data to a different (and less expensive tier) of storage, but also making sure that the information can be easily recalled upon request.
In the mainframe world, archiving is optimized only for the use of tape. That means an on premises solution, which while useful, lacks some of the benefits of a hybrid cloud solution that IBM TCT supports. Let’s consider that more closely.


Transparent Cloud Tiering Changes the Mainframe Archiving Architecture to Enable the Hybrid Cloud
Archiving data on the mainframe typically requires the use of DFSMShsm software on a z System, the Hierarchical Storage Manager component of the Data Facility Storage Management Subsystem which runs on z Systems. Up to now, migrating data from a DS8880 for archiving purposes to physical or virtual tape required the data to be ingested from the DS8880 and then written by DFSMShsm to the archiving physical or virtual tape target. The resulting CPU resources required to do this by running DFSMShsm on a z System could be quite large depending on how much data movement is required.
In contrast, TCT offloads the data movement responsibility to the DS8880 thus removing the CPU burden from the z System. DFSMShsm still determines the data to be migrated (typically the age that data for an application needs to reach after creation before being migrated) to the TCT software. DFSMShsm determines the physical extents associated with the data and passes that to the TCT software. TCT then does the heavy lifting of actually moving the data that is being archived to its new home.


That target can be an IBM TS7700 tape system on-premises as an object storage target, but without the CPU overhead on the z System.
However, the real focus of TCT is to be able to migrate data from the DS8880 storage to hybrid cloud environments. One such target is IBM Cloud Object Storage, where users have the choice to run on premises or off premises as a service on a multi-tenant public cloud. A second type of target is a public cloud where the data is typically stored as blocks. The first public cloud that IBM has announced its own IBM Bluemix, but the company says that support for Amazon S3 is expected sometime during the second half of 2017.


Direct data transfers from IBM DS8880 systems to hybrid cloud environments substantially removes the archiving burden from z Systems and that is obviously a good thing but that is not the only benefit. Archive operations on z Systems are not only simplified, as well, but new choices enabled by TCT may very well result in capital and operating expense savings. One big advantage is being able to take advantage of data services that are already provided by the hybrid cloud. Notably that increases the options and choices for data protection, such as for backup and disaster recovery processes.


Mesabi Musings
Keeping tons of less frequently accessed older data on a primary production mainframe storage system is expensive. The right move is to archive this data to a different storage tier, but, until now, z Systems users only had the choice of migrating the data to a physical or virtual tape archives on-premises. IBM’s introduction of Transparent Cloud Tiering expands the archiving storage tiers to the hybrid cloud by including public cloud as a service option. IBM’s new TCT architecture, unloads the z System MIPS burden of archival data migration to a DS8880 storage system, provides greater flexibility that can lead to possible capital or operating cost savings as well and provides more choices for data services, such as for data protection.


In one form or another, IBM’s z Systems have been around for over fifty years, but the company keeps z Systems and its associated storage always fresh and new by taking advantage of the latest technological trends, such as the hybrid cloud, while at the same time preserving the robust heritage that continues to make the mainframe relevant and vital. IBM’s Transparent Cloud Tiering capability is simply the latest example of this process in action. And that is a good thing!