- Introduction
- Description
- Benefits
- Resources
- History
The EMC Disk Library for mainframe (DLm) is a Virtual Tape Library for IBM compatible mainframes. All the "tape drives" in an DLm are emulated devices where tapes are actually disk files located on backend storage. Each DLm VTE (node) is attached to an IBM compatible mainframe using FICON or ESCON channels, and typically connects to backend NAS storage using dual-channel gigabit network connections.
DTS Software leveraged existing DTS technology to create the DLm Control Center (DCC). The new product borrows components from SCC Monitor, the Allocation Control Center (ACC), and Easy/Exit.
Note: DCC was originally developed for the Bus-Tech Mainframe Data Library (MDL), and was originally called the "MDL Control Center (MCC)". After EMC purchased Bus-Tech, MCC was renamed to "DLm Control Center (DCC)".
DCC is designed to:
-
ease a DLm installation
-
manage the devices through the channel interface using a system console, TSO/ISPF, a PC GUI application, and/or an Apple iPhone/iPad.
-
monitor DLms using the channel or SNMP TCP/IP interface to trap important DLm events, and then notify support personnel via logs, console or TSO messages, email, and/or text messages. Note: Virtuent 7 firmware is currently required for monitoring through the channel interface.
-
control OS device allocation without using an SMS Manual Tape Library (MTL) - JES2 and JES3 supported
-
JCL keyword extensions for DLm Allocation (IBM z/OS only)
-
perform load balancing for multi-VTE DLm configurations - JES2 and JES3 supported
-
provide a tape migration tool specifically designed for the DLm
-
provide scratch exits to keep Tape Management and DLm scratch pools synchronized
-
designed for IBM z/OS, Hitachi VOS3 and Fujitsu MSP
-
designed for the EMC Virtuent 6 (DLm 2.x) and Virtuent 7 software releases
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
- TSO/ISPF
- 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.
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.
Note: The webinars are recorded in .wmv format using the GoToMeeting video Codec. If your media player cannot play the requested webinar, please visit the GoToMeeting website to install the GoToMeeting Codec.
| WEBINARS | |||
| Mar 24 2011 | 60.22 MB | 55 Minutes | |
SMS Managed Manual Tape – What is it and how does it compare to DLMALLOC |
Apr 26 2011 | 94.68 MB | 60 Minutes |
| May 26 2011 | 50.06 MB | 47 Minutes | |
| Jul 21 2011 | 68.94 MB | 61 Minutes | |
| Sep 20 2011 | 64.79 MB | 50 Minutes | |
| Oct 25 2011 | 68.34 MB | 56 Minutes | |
| Dec 01 2011 | 75.25 MB | 67 Minutes | |
| Jan 26 2012 | 63.60 MB | 53 Minutes | |
| MARKETING LITERATURE | |||
| Jun 03 2011 | 51.83 KB | ||
| Jun 03 2011 | 43.17 KB | ||
| PRODUCT MANUALS | |||
| Feb 20 2012 | 2.09 MB | ||
| Feb 20 2012 | 946.19 KB | ||
| Feb 20 2012 | 1.06 MB | ||
| Feb 20 2012 | 569.30 KB |
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)".