DLm Control Center (DCC)

DLm Control Center (DCC) is an invaluable tool for managing virtual tape devices in the Dell/EMC Disk Library for Mainframe (DLm). With DCC, administrators have complete control over the DLm system from z/OS, without the need to switch to unfamiliar GUI windows or browser interfaces. DCC can control the allocation of tape drives, issue commands, display status, and migrate data, all from easy-to-use ISPF or batch interfaces. DCC provides many features, including:

  • Device allocation with or without the need for SMS manual tape libraries (MTLs)
  • Command and device management via channel interfaces and TSO/ISPF or console commands
  • Automatically monitor and trap of important Dlm events and notify administrators of problems
  • Tape management exits and reports insure that TMS, OAM, and device inventory are always in sync
  • Unique DLMCLONE and DLMCOPY high-speed migration utilities
  • And much more!
When a EMC DLm configuration is installed at a customer site, from an operating system point of view, the DLm VTEs are simply groups of tape drives. From an operations standpoint, the DLm presents several challenges which DLm Control Center (DCC) has been designed to address:

Command Interface

DCC can interface to DLms through the channel interface. For command processing, the product temporarily reserves a device in a DLm VTE for command execution. As soon as the command completes, the device is released. DCC can issue commands from:

  • operator consoles
  • batch jobs
  • the SCC Explorer PC GUI application from DTS Software
  • an Apple iPhone or iPad

Monitoring Interface

The new product also has the ability to monitor the DLm event log using either the Channel Interface or SNMP. Event triggers can be used to log messages to a data set, SMF records, and/or send messages to operations staff via the operator console, email or text messages. Note: Monitoring a DLm through the channel interface requires Virtuent 7 firmware.

Tape Migration

To streamline the migration process, DTS Software provides the DLMCLONE migration utility. Exact copies of tapes are created in a EMC DLm library using the same volume name and device type. The system catalogs and tape management systems are not affected – only the “location” of the tape is changed. The application also corrects records in the Tape Configuration Database (TCDB). To aid migration throughput, the DLMCLONE utility can perform up to 99 concurrent tape copies to migrate tapes to a DLm.

Allocation Interface

The DCC DLm Allocation interface can be used to control device allocation. If a requested tape resides in a DLm library, only the library devices are eligible for the allocation request. When non-library tapes are requested, DLMALLOC removes the DLm tape devices from the eligible device list. The interface can also perform unit affinity splits if DD statements try to share the same device, but volumes between the DDs are inside/outside the DLm. Lastly, DCC identifies the condition where a multi-volume tape dataset uses volumes inside/outside the DLm. In this case, the product uses installation defined rules to handle the conditions. By default, the rules issue a warning message, and then terminates the job.

In JES2 environments, DLMALLOC works with MVS Allocation to direct tape requests. In JES3 environments were JES3 SETUP processing is used to select devices before job initiation, DLMALLOC uses two JES3 user exits to direct tape requests to the appropriate devices.

Load Balancing

Mainframes have historically been very good at optimizing I/O performance on channels connections. However, installations that have multi-VTE DLm configurations present serious optimization challenges. Due to the number of emulated devices on each VTE, and the inability to access the I/O load on the network connections to the backend storage, the network connections for some VTEs can become I/O saturated while others are left idle. This problem is especially prevalent in JES3 installations and DLm configurations that have 1000+ tape devices configured.

The DLm Control Center (DCC) uses device selection technology developed for the DTS DASD products to enable load balancing across DLm VTEs. DCC influences the device selection during Allocation. Allocation builds an Eligible Device List (EDL) for the tape request, and DCC uses a load balancing selection algorithm to spread the tape requests between the DLm VTEs.

Note: The Load Balancing facility can be used with DLMALLOC or SMS Tape (MTL) controlled DLms, and in both JES2 and JES3 environments.

Scratch Exit

When a tape management system (TMS) changes the status of a tape to “scratch”, the TMS systems calls an exit that can be used by DCC to intercept the scratch request. DCC can immediately notify the DLm that the tape is now scratch. This allows the DLm to have the scratch status synched real-time with the tape management system. The currently supported TMS systems: IBM RMM.

Write-Ring Support

The EMC DLm devices do not have the concept of read-only tape protection. When physical tapes were common, after a tape was created operators could pull the write-ring to disable future updates. DCC has a facility to write protect tape volumes by manipulating the Read-Only flag on the tape emulation file located on the backend storage device. The flag can be displayed or changed using the the DCC DLMCMD TSO or console command, or manipulated using the DLMOPT keyword on a DD statement or the DLMALLOC rules language to create policies to selectively protect output tapes. When a tape emulation file is marked as read-only, the DLm will not modify the virtual tape. Mainframe users receive the same console and JES messages that would occur when a write-ring is removed.

DCC  provides a wide range of benefits that will ultimately allow installations to more effectively install, implement and manage the Disk Library for mainframe (DLm). This will be accomplished by providing:

Robust Command and Monitoring Interface

  • Modern, efficient and familiar interface
  • ISPF/TSO, GUI, z/OS system console, batch, smartphone
  • Capture DLm events via an SNMP or the channel interface

Advanced Intelligent Device Selection

  • Advanced Allocation Control ensures proper device selection
  • Eliminates the need for JCL changes
  • Eliminates the need for OAM or SMS management of DLm tapes
  • Provides policies for scratch, multivolume and unit-affinity requests

Efficient Transition via Automated Migration Manager

  • Automates and manages the migration of tape libraries
  • Unique ‘cloning’ technology for maximum accuracy & effectiveness
  • NO updates to TMS required
  • Provides simplicity to complex issues

Load Balancing Optimization

  • Optimizes performance for multi-VTE DLms
  • Automated via a device selection algorithm
The marketing literature and webinars are available to all visitors. The product manuals are only available to registered customers and companies trialing DTS products – login is required. To request authorized access, please complete the Registration form. DTS customer support will review your request. Upon approval, you will receive access notification by E-mail within one business day.

Introduction to Virtual Tape and Tape Management Feb 21
139 MB 60 Minutes
Understanding How to Control, Manage, and Report on the EMC DLm May 20 2014 93.82 MB 58 Minutes
Virtual Tape Migration to DLm – User Experience Overview Apr 23
89.06 MB 54 Minutes

An Advanced Dashboard Monitor for Virtual Tape Systems

Oct 25
52.44 MB 35 Minutes

Learn About Using an SMS-Managed Manual Tape Library

Mar 27 2012 76.21 MB 51 Minutes

Tape Device Migration Strategies

Jan 26
70.60 MB 53 Minutes

Management and Migrating Tape Volumes on the DLm with DCC

Dec 01 2011 113.81 MB 67 Minutes
Managing Your z_OS Storage Environment More Efficiently Oct 25
99.80 MB 56 Minutes

Migrating Tape Volumes to the DLm_MDL with DCC

Sep 20 2011 81.78 MB 50 Minutes

Data Deduplication – What is it and what can it do for me

Jul 21
77.93 MB 61 Minutes

Managing and Monitoring the DLm-MDL from zOS

May 26 2011 81.06 MB 47 Minutes

SMS Managed Manual Tape – What is it and how does it compare to DLMALLOC

Apr 26
119.30 MB 60 Minutes
Controlling Tape-on-Disk with DCC Mar 24 2011 97.07 MB 55 Minutes
DCC White Paper: Issues in Tape Allocation Jun 03
51.83 KB
DLm Control Center (DCC) Jun 03
43.17 KB
DLm Control Center (DCC) User’s Guide May 24 2018 5.95 MB
Product Installation Guide Nov 01 2018 1.04 MB
Rule Language Programming Guide May 24 2018 1.55 MB
SCC Messages Manual Nov 15 2018 1.02 MB
“DCC was very easy to install and implement.  It makes monitoring and administration of the EMC DLm very easy and much more robust than the EMC provided tools.  Being able to have DCC automatically scratch tapes on the DLm is a big advantage over having to run a separate process.”

Large Utility Company

“I’d say DCC was a success!  You were correct that it did go quickly once we were able to start the jobs and let them run.  The DTS support team were real troopers to get us through some of the internal weirdness we have. Thanks to you all!!!! “

Indiana Farm Bureau Insurance

“I want to say thank you to DTS Software. They were a key vendor in both strategic and tactical roles. Special thanks to the technology resources at DTS. It was the DTS sauce that made the VTL conversation a hit on the data center floor.”

BJC HealthCare

In mid-2008, the DTS distributor in Japan (CLC) requested permission to use ACC to control tape allocation for Bus-Tech MDL migration projects. This led to the discovery that DTS and Bus-Tech shared the same distributor in Japan, and that our offices in Raleigh, NC are located approximately six miles apart. After learning more about the MDL capabilities and the new MDL channel interface being introduced by Bus-Tech in Virtuent 7, DTS started development of MCC in late 2009 using components from existing DTS products. The resulting product far exceeded the initial allocation control product and migration tool envisioned early in the project. DTS released MCC in late 2010.

Note: After EMC purchased Bus-Tech in early 2011, MCC was renamed to “DLm Control Center (DCC)”.