Buried in IBM’s Q4 2010 earnings report were two factoids that reveal the key role that the mainframe continues to play in enterprise environments today – IBM reported a 58% increase in MIPs growth and a 69% increase in mainframe sales. These increases clearly signal that the mainframe is alive and well but it also means that the mainframe continues to generate data that needs to be accessed, protected, stored and recovered in ways unique to the mainframe. It is these specific needs that EMC’s newly announced Disk Library for the mainframe, the DLm6000, addresses even as it puts the squeeze on the use of tape in mainframe environments.
As part of its quarterly earnings IBM breaks out revenue by Services, Software and Hardware. It was in the Hardware section that IBM shared these year-over-year increases in both its MIPS growth and mainframe sales.
But in what can only be described as stellar growth for the mainframe, it is creating a new problem in supporting and using it: a shortage of storage solutions appropriately configured for the various mainframe use cases.
What makes the mainframe somewhat unique in the world of computing is that archival, backup and production data are more easily intermixed and accessed by the mainframe than in the open systems world. Clearly the mainframe still primarily does backups using tape as a target and recoveries using tape as the source.
But where the mainframe differs from open systems environments is that it will access and store data on tape for purposes other than backup and recovery. For instance, the mainframe may archive data to tape, do an HSM migration, use it as a work or scratch tape or some combination of all of these.
It is not that tape storage systems cannot be used in such a manner in open systems environments but I have rarely encountered them used in such a way whereas they are much more common in mainframe environments.
It is for these reasons that when IBM typically configures a backupstorage solution for its mainframe clients, it tends to use some
combination of tape and disk to both satisfy these varying use cases
that still exist in mainframe environments as well as meet growing users
demands for better performance and cost containment.
It is these specific challenges that EMC addresses with its recently
announced Disk Library for the Mainframe, the DLm6000. But what EMC does
to meet these multifaceted requirements is that it takes them on
without needing to make tape part of its DLm6000 solution. To do so, the
EMC DLm6000 now offers the option to be configured for concurrent mixed
storage flexibility.
The DLm6000 is a virtual tape library (VTL) solution that consists of
two components:
- The virtual tape emulation controller (VTEC) with 2 – 6
controllers - The backend storage
In order for the DLm6000 to
satisfy the multiple use cases that exist in mainframe environments, the
backend storage of the DLm6000 may consist of either one VNX7500, one
Data Domain 890, two of each or one of each in what is referred to as
concurrent mixed storage flexibility.
In this configuration, if the DLm6000 is used exclusively used for
backup and recovery or archive data, the backend storage is more than
likely configured with two DD890s so it can scale to the highest
possible logical storage capacity (5.7 petabytes assuming a 10:1
deduplication ratio.)
Conversely if the DLm6000 is going to primarily be used for HSM
migrations or work tapes, it would make more sense to configure it with
two VNX7500s. In this configuration, EMC has demonstrated that the
DLm6000 can achieve maximum throughput speeds of over 2 Gb/second.
Yet in releasing the DLm6000, EMC wanted to do more than optimize storage capacity and performance, it wanted to make the case for users to switch from tape to disk even more compelling. To accomplish that, it sought to make it fit more seamlessly into mainframe environments while also removing the hassles with moving data offsite.
To make the DLm6000 easier to manage, EMC updated the DLm6000 software. In this update, z/OS can now recognize the DLm6000 so mainframe administrators can manage it from the z/OS console as any other storage device.
To facilitate the offsite movement of data, the DLm6000’s took advantage of the replication features found on both the VNX7500 and the DD890. These two systems both connect to the VTEC controllers via the NFS protocol which permits the creation of individual folders that store specific data.
Since each of these systems support the configuration of replication at a folder level, enterprises can send specific data to folders and then using the DLm6000 designate those folders to replicate the data in those folders to a DLm6000 at another site. This helps to minimize the replication of data that is not needed for disaster recovery (such as what might be included on scratch/work tapes) while ensuring that data that is needed remotely is promptly replicated and eliminating the need for the creation and handling of tapes.
IBM’s recent quarterly results show that the mainframe is alive and well. But the EMC DLm6000 also demonstrates that storage innovation in the mainframe environment is continuing as well. By EMC configuring the DLm6000 for use with the VNX7500, the DD890 or both, enterprises can get performance, optimized capacity or the best of both even as they get new abilities to manage the DLm6000 from the z/OS console, increased flexibility to recover data remotely and remove the cost and complexity associated with managing tape in their mainframe environment.