Mainframe Controls Tape Robot

The LMS (Library Management Subsystem) software is installed on the OS/390 mainframe, and facilitates communication via a control link with the L2000 tape robot from COMPAREX. The tapes used in the L2000 are linked to a backup server via SCSI. An additional control link is connected between the backup server and the LMS software. For data operations, the backup server is connected to the COMPAREX RAID system. The individual application servers which hold the databases and R/3 systems are linked via SCSI connections to the RAID system, where domains are set up for the databases.
In future, the SCSI connections will be replaced by Fibre Channel links so that several systems can be connected on one channel using an FC hub. NORDAC is currently operating around 30 systems, ten of which are already connected to the central RAID system.

Step-By-Step Mirroring with Split Mirror Backup

The individual systems are mirrored onto a single storage area. Helge Leimgrübler, project manager at NORDAC, explains the procedure. "We take the first system and generate a mirror of it. The mirror is split and the data from the mirror is copied via the backup server to the L2000. After this step, the mirror is completely detached from the first system and is assigned to the second. The data from the second system is then synchronised with the mirror and transferred via the backup server to the tape library."
Under normal circumstances, the project manager explains, each system would need a client plus installed software for each client. The advantage of the new backup system, however, is that you only need one extra client on the backup server.

L2000 Robot for Mainframe and NT Data

At the end of 1999, COMPAREX provided an L2000 test library. "With the support of COMPAREX, we set up a link between the OS/390 and a backup server using the LMS software. This means that primary control lies in the mainframe", explains Jürgen Leimgrübler, director at NORDAC.
The L2000 robot has a total capacity of over 500 cartridges and can accommodate up to eight drives in its current configuration. High speeds were achieved during the Split Mirror Backup tests. As Helge Leimgrübler explains, "We have a maximum backup time of one hour for 30 GB and a recovery time of less than an hour too. The L2000 is the optimum solution for us, because it can be expanded to accommodate additional drives and cartridge stations if we need to."

Non-Disruptive Backups

"In the long term, the main benefit we expect from using a centralised storage system and the L2000 robot is considerable time savings during backup", explains Jürgen Leimgrübler.
"With the Split Mirror Backup method, we no longer have to worry about getting everything done in a short window of time. We'll be able to back up entire databases while they are running, without suffering any noticeable performance losses." Cost savings are also a factor for consideration, since the storage space required on the RAID system is considerably reduced because only one mirror is needed. The performance of the individual R/3 systems is also dramatically improved. "We implemented the L2000 because we realised that we were going to need 1 TB of additional disk storage capacity every year, so we needed a scaleable ATL-system capable of meeting the growth in data", explains Jürgen Leimgrübler.

NORDAC Rechenzentrumsgesellschaft mbH

NORDAC mbH was founded as the IT company of Drägerwerk AG in 1995, and has since then made an excellent name for itself as a provider of outsourced services. Today the computer centre company serves numerous customers with a wide range of platforms.