EMC DLm6000 announcement
EMC recently announced a new version of their disk library for mainframe environments the DLm 6000 with new backend storage capabilities.
For the first time last year EMC rolled out a new deduplicition capability for their DLm product using a Data Domain deduplication appliance. At that time the DLMm960 product used the Celerra NS960 and the then current Data Domain DD880 appliance.
The new DLm6000 upgrades the backend hardware to the latest VNX 7500 and the newest Data Domain DD890 and upgrades the frontend with new Bustec hardware. The new system supports up to 2GB/s of throughput and scales to 5.7PB of logical capacity (after deduplication). With all the new hardware capabilities EMC believes their new system is 2X faster than the nearest mainframe VTL competitor.
The new Bustec frontent supports up to 6 virtual tape engines (VTEs) emulating IBM tape drives. Tape volumes are stored as files and are accessible across all tape engines. VTEs handle tape image creation and writes these images to the backend storage.
Recall that with the previous generation DLm960 one could select between alternative backend targets for virtual tape activity, i.e., normal disk storage for high throughput, non-deduplicatable data or Data Domain storage for highly deduplicatable data such as full backups.
In addition to the hardware upgrades, the new DLm6000 centralizes operations utilizing the z/OS console. Also the DLm6000 now provides finer grained replication available now at the file system vs. disk target level.
Furthermore, EMC also offers a Data Domain systems using Bustec VTE’s, in a gateway configuration, for those customers just needing backup services. In these configurations, the backend Data Domain appliance can be shared between mainframe and open system environments.
Tape use in mainframe environments
As most mainframe environments matured in an environment where tape was by far the most economical storage alternative, tape continues to be heavily used in this space. Not only is tape employed as a backup medium, but it also plays a critical role in secondary data storage, such as for DFHSM (hierarchical storage manager) as a tier 2 or 3 backing store for disk datasets. Also in some situations, tape can be exploited as primary storage such as for temporary workspaces used in large dataset calculations and processing in this sense a pre-cursor to today’s big data analytics, using batch processing.
For example, one customer using the DLm6000 for HSM backing store reduced wait times to 1 second on average from the 90 seconds they saw previously with tape infrastructure and as such, provided $450K in annual personnel savings. The other major concern for this customer was DR readiness. With the new DLm6000 data replication services they were able to verify that data was available at their secondary sites.
There is no doubt that in open systems, traditional tape markets are giving way to disk-based solutions, relegating tape to more long-term storage archive applications. Mainframes, due to their long history, probably use tape more extensively and efficiently than open systems and remain one of the last bastions of heavy tape use outside data archive.
With the introduction last year of DLm960 and this year’s DLm6000, EMC is starting to attack this remaining stronghold of tape use. Nevertheless, we predict mainframes will not migrate quickly from a relatively tape intensive environment to a disk based solution.
For instance, mainframe systems that combine the use of disk and physical tape have been around from StorageTek since the late-90’s and from IBM for about 3 years. These products primarily cache data to disk and then migrate it to tape. As such, systems like these can provide an alternate, hybrid disk accelerated tape path for traditional tape mainframe workloads. Further, many customers have already invested in tape automation and when doing so, find that tape storage economics can be hard to beat.
On the other hand, EMC is a disk-only system, doing away with tape infrastructure altogether. Moreover, EMC brings deduplication technology to this market, which the other hybrid disk and physical tape systems currently lack. Deduplication turned out to be the key technology that caused open system backup to move from physical tape to disk based systems. EMC is betting that deduplication will have a similar impact in the more traditional mainframe environment. But mainframe tape use is much more varied than simply backups, which is why DLm6000 has two target backends.
However, at least one things for sure, mainframes are becoming a new battleground in the age-old conflict between disk and tape. One that originally started there, over 40 years ago, with IBM’s own admission that tape was dead.
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Silverton Consulting, Inc. is a Storage, Strategy & Systems consulting services company, based in the USA offering products and services to the data storage community.