Two companies are looking at a new technology of combining magnetic and optical disks in one box to provide both data access and archiving. They believe that the combination will offer e a good fit for the storage and protection of so-called fixed content data.

Plasmon and Nexsan hope to address the issues that hamper existing technologies: magnetic disk provides fast access but is no use for long term storage, storage over decades, on two grounds. Its failure rate is too high and it can't be removed for disaster recovery via off-site vaulting. In the recent past its capacity was too small and its cost too high for the storage of huge amounts of data anyway.

The general answer to this unsuitability has been to backup data to tape and use that for long-term storage of large amounts of data. Where the data has to be archived for decades with a guarantee of it being unaltered then write-once/read many (WORM) optical disk has been used, either magneto-optical or consumer CD/DVD media. Thus a split has emerged between tape backup of changeable data and optical archive of static data.

But Plasmon and Nexsan hope to change the storage market on its head. Plasmon uses a NAS drive array whereas Nexsan uses a CAS front end.

The Plasmon UDO Archive Appliance uses 30GB UDO (ultra density optical) disks to archive data. Sitting in front (logically) of these is a NAS RAIDtec array, offering from 960GB to 19TB capacity. The product comes with system management and archive software.

Nexsan Technologies and DISC GmbH have introduced a similar combined magnetic/optical product for fixed content data. The product adds DISC's 23.3GB optical disks to Nexsan's serial ATA (SATA) Assureon server and drive array. Assureon offers content-addressed storage (CAS) facilities meaning that server applications don't see a standard CIFS or NFS interface. Maximum optical capacity is 16TB.

It will be interesting to see if tape vendors offering disk-to-disk backup products strap optical disk-based back ends onto them. That way they could get back into a fixed content archive market that seems to be departing from them at a rate of knots.