Mainframes don't de-dupe: Shoden shows 'em how it's done

Peter Williams

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Published: 19th November, 2008
Content Copyright © 2008 Bloor. All Rights Reserved.

De-duplication of data during backup to save backup space is now common in the distributed and open systems market. It can yield upwards of 95% backup disk space savings and drastically alter the economics calculation related to using tape or disk for archiving. Yet de-dupe has largely by-passed the mainframe world so far.

There are some technical reasons for this to do with the complex way in which mainframes store the different data types; yet, if these are overcome, huge storage savings are there to be had. It means a smaller storage footprint, lower running costs, less energy and cooling and, when data is transmitted to remote sites, a huge saving on WAN transmission bandwidth and time. These factors help make de-dupe attractive in these tough economic times.

Meanwhile, the mainframe world is particularly wedded to tape for backup and archive; that tends to mean long recovery times, whereas de-dupe solutions that write to disk can be recovered much faster.

I mention this because z/OS mainframe users in one country, South Africa, are already using a de-dupe solution successfully. The company that supplies it—Shoden Data Systems—is now launching in the UK through a subsidiary.

A major retailer with z/OS mainframes, Edcon (South Africa's nearest equivalent to M&S with a $3bn turnover), has so far achieved an 11:1 (91%) space-saving using Shoden's solution (which incorporates Data Domain's market-leading de-dupe appliance). It has also eliminated tape altogether and uses de-duped data transmission to a remote site as part of its disaster recovery (DR) plan.

According to Shoden Data Systems UK's CEO John Taffinder, Edcon also achieves much lower maintenance costs, achieves simplified and faster restores, and has re-deployed tape staff.

"There is a problem with tape [on mainframes] but people don't want to spend," said Taffinder. "It is typical to take 3–5 hours to recover and most say they are happy with 24 hour recovery (which in practice means two days to get back to normal)." This problem is of course greatest if tapes need to be physically retrieved from offsite stores.

He added that data migration was much easier with disk, tape libraries were expensive to maintain and disk reliability was higher. I also concur with him that de-dupe should be attractive to mainframers everywhere. Right now, Shoden's solution seems to be the only one out there; so its short-term success may boil down to the market's perception of the economic value.

Edcon avoided purchasing a new tape robot or smaller virtual tape library (VTL) to replace their now unsupportable IBM tape robot; it found the Shoden solution worked out more economical in addition to gaining all the added benefits just described. South Africa is not UK of course but similar ROI calculations can be made here.

How the Shoden solution works is conceptually simple and largely transparent to mainframe operation. ‘QuickRecover' uses Luminex VTL engine(s) to translate the processed data from the mainframe as though going to an IBM 3940 tape drive—taking the processing load away from the mainframe. It uses fibre channel (6-8 FICONs) and allows 1-2 ESCON or FICON tape emulations in changing the data into a format that the Data Domain de-dupe NAS appliance can handle; the output is then captured on an Intel Xeon-based Hitachi blade server (not otherwise available in the UK).

This process is managed through Shoden's own mainframe management GUI console using a management server sitting within the VTL engine. This handles sizing and configurability, recovery management, error logging and dashboard statistics such as de-dupe ratios, performance and pain points. Flexibility is built in so, for instance, it can be arranged as one data set per "tape cartridge".

Shoden in the UK is also able to take immediate advantage of the group's well-established and English-speaking 24x7 first-line support service from South Africa. So while the UK mainframe market is not huge, start-up teething troubles ought to be minimised. Mainframe users seeking to cut costs quickly would do worse than take a close look at how Shoden does it.

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