Fujitsu Siemens Computer is not the first choice you think of when asked to name a store supplier with a world-leading storage product. But FSC might just have pipped every other supplier with its CentricStor virtual tape library (VTL) product.

A virtual tape product stores backup data on disk before sending it to tape. The write to the virtual tape takes place at disk speed, much faster than streaming to a tape. Thus backup time windows can be reduced, also file restoration time can be significantly reduced if the file is restored from disk, acting as a cache in front of tape drives.

VTL suppliers and products
Virtual tape suppliers include:-

- ADIC PathLight VX.
- FalconStor supplied by EMC (Clariion Disk Library) and McDATA (Via CNT acquisition which included UltraNet Storage Server).
- Maxxan with its SVT 100 appliance.
- NetApp with its NearStore VTL, courtesy of its Alacritus acquisition.
- Overland Data's Reo 9000
- Quantum, through its Certance acquisition, with the DX100, DX3000 and other DX products. Leonhardt says these are in the DAT/DDS area although Quantum offers support of its own DLT format.
- Sepaton, supplied by HP. Ironically HP is a CentricStor customer, through its acquisition of a German service provider.
- SpectraLogic with its RXT Sabre product family.

FSC partners a lot of storage suppliers and resells, after integration testing, third-party product. However, CentricStor is different. Leonhardt said: " CentricStor is not just an EMC resell; it's a strategic product." All the intellectual property is owned by FSC.

VTL and disk-to-disk backup
The virtual tape market is different from the disk-to-disk (D2D) backup market because it always involved a tape and disk product. The data is always written to tape. A D2D box need have no tape and can is used just as a disk backup product. The acronym D2D2T stands for disk-to-disk-to tape.

VTL history
Reiner Leonhardt is FSC's senior product director in the storage division. He presents the history of virtual tapes thus: in the beginning IBM and StorageTek produced virtual tape drives to speed up tape operation on mainframes. Mainframes use tape in a more active way than open systems - Windows and Unix/Linux - servers, which use tape for regular backups.

Mainframe operation was getting affected by the time it took to write data to and read data from tape. So disk systems were interposed between the mainframe and its tape drives. They presented themselves as real tape drives and read and wrote data at disk speed rather than tape speed.

FSC had its own mainframe, the BS2000, and wanted/needed to produce a virtual tape disk cache as well. FSC took a decision to produce a self-contained virtual tape appliance that did not need software on the host mainframe. It sat on the mainframe's channel link to a tape drive and, in effect, spoofed the mainframe that it was an actual tape drive, meaning no change to the mainframe software environment.

The IBM VTS and StorageTek VSM virtual tapes, according to Reiner, involved software on the hosts.

What all three VTLs (virtual tape libraries) did was consolidate many tape drives. The disk cache wrote files to be stored on tape in such a way that tape utilisation increased significantly; customers didn't need so many cartridges. They also wrote to tape without affecting the host's operation, meaning fewer actual tape drives were needed.

VTLs then migrated to open systems once super tapes (LTO, SDLT) became popular and backup time started lengthening and lengthening.

FSC, IBM, StorageTek aka Sun DMG, and open systems
All three mainframe VTL suppliers have ported their VTLs to open systems servers. They kept the existing mainframe ESCON and FICON connectivity and added in Fibre Channel.

FSC had a much easier porting job because it had no host software needing to be changed. So FSC got its VTL in the open systems arena well before IBM and StorageTek, sometime in 2003 in fact.

IBM has ported VTS to Windows and Unix. StorageTek, pre-Sun time, also ported its VSM product to the Windows, AIX and Solaris environments.

Good VTLs write data from the disk cache to the actual tape drives trnsparently, from the server point of view, and with user-settable policies. Leonhardt says CentricStor has both these properties.

A VTL is the more generally useful the more tape formats, tape libraries and servers it supports. Leonhardt provided the following data for CentricStor:-

Hosts supported:-

1. Mainframe
- IBM - Z/OS, OS/390, OS/4-00, VM/VSE
- Bull - GCOS 8
- Fujitsu - MSP, XSP, VME (ICL)
- FSC - BS2000/OSD

2. Open systems
- AIX
- HP-UX
- Reliant UNIX
- Solaris
- SuSE and Red Hat Linux
- Windows 2003, Windows 2000, Windows NT

3. NAS NDMP backup
- EMC Celerra
- NetApp filer

It is also the more useful the more backup products are known to work with it and the more tape libraries and tape formats it works with. A VTL aiming to be sold into the mainframe area, for example, needs to support mainframe connectivity, mainframe libraries from IBM and StorageTek and mainframe tape formats from IBM and StorageTek.

The CentricStor products support ADIC, Fujitsu, FSC, IBM and StorageTek libraries and LTO 1, 2 and 3, IBM 3590 and 3592, Fujitsu 3591, and StorageTek T9840 and T9940 formats. Quantum's SDLT is an obvious gap in its format coverage. Whether this matters is debatable.

Competitive status
Other virtual tape vendors include Sepaton with HP, ADIC with its PathLight, and Maxxan.

FSC wants to be the world-wide leader in the D2D2T market, Leonhardt saying: "We don't want to be the leader in the D2D backp market. We want to be the leader in the tape consolidation market."

Leonhardt and Josh Krischer, an ex-Gartner analyst, provided the following market size and rough shipment information:-

Number of installed systems: 6,000 - 7,000 mainly in mainframe sites
Main unit shippers: IBM and StorageTek (Sun DMG) at rates of approximately 250 and 300 units per year respectively.
FSC market share is about 8 percent with about 400 installations and an annual ship rate of around 50 units.
ADIC has shipped very few PathLights, ditto Overland with its VTL products.

For FSC to become a market leader it has to increase its annual VTL run rate eightfold. This is a big target and, perhaps, becoming the leading VTL shipper in Europe or the EMEA region is moe realistic.

Prospects
The picture drawn by Leonhardt is that CentricStor supports the broadest range of hosts, tape formats and libraries compared to any other VTL. It probably has the third largest installed base after IBM and StorageTek and much better open systems credentials than either of those two suppliers' products. It has more 'traction' in the market than any pure open systems VTL supplier.

What is surprising is that, on the basis of the FSC/Krischer figures so very few VTLs have been bought by non-mainframe customers. Anyone aiming to be the VTL market leader in enterprises with open systems, which is where the market opportunity is - we take it as read that most if not all mainframe sites needing a VTL have already got one - will need very good channel coverage from partners able to sell VTLs. It's not just a box sale.

On the face of it ADIC, a leading tape library shipper, with EMC as a partner, ought to have a very good opportunity to go to all its tape library customers and say 'put a Pathlight VX in front of your ADIC Scalar library'. Equally HP, with its many enterprise customers has a good opportunity to put Sepaton in front of them and deny FSC. Ditto NetApp with its customers.

If the FSC/Krischer figures are right then no one supplier has a commanding lead in the, relatively large, open systems VTL market and the opportunity is wide open.

One factor may be the integration of the pair of VTL storage tiers, disk and tape, in an overall information lifecycle management (ILM) set up. To the extent that this is important then VTL success is likely to be influenced by the quality of product integration with ILM product suppliers.

The biggest single incremental and significant advance in data security and system up-time will likely come from a combination of VTL and D2D. A recent NetApp survey showed the lamentable data security conditions in British business. It also showed that NetApp is serious about this market. FSC is going to have to convince customers that it has the best VTL product range and gather a well-qualified and effective channel around it.