Virtual tape libraries made a big splash when introduced earlier in the decade, then they sort of faded away. Now it looks as if they're making a comeback, only this time we're seeing a significant push toward mid-market and lower-end solutions.
It's no surprise, though, that most of the newest systems are reworked versions of existing high-end platforms. But when it comes to back-up, all-disk solutions don't have the market sewn up just yet.
Diligent Technologies is one of the latest VTL vendors targeting smaller firms. The company has two new versions of its ProtecTier systems: an entry-level configuration that scales from 8 to 20 terabytes, and a higher-end all-software version based on multiple quad-core server nodes.
Also new to the market are so-called hybrid systems that mix VTLs with straight disk storage or traditional tape machines. Overland Storage is offering a new mid-market approach with the REO 9100 that uses serial advanced technology attachment-based Fibre Channel or Internet small computer system interface with 750 gigabye drives to allow installations to scale up to 66 TB. Even higher up the chain is the Spectra Logic T950, which brings together an eight-frame tape library with partitioning software to scale up to 16 petabytes of compressed storage.
Of course, established vendors aren't sitting quietly while the upstarts steal their thunder. EMC recently introduced the Disk Library 6000, billed as the largest open-systems VTL with a maximum capacity of 1.8 PB of compressed storage and a backup rate of 11 TB an hour.
But even the traditional VTL may be seen as old hat before too long. The newest twist is the Virtual Tape Array touted by NetApp. The idea is to do away with simulating physical robotic tape movement from drive to drive and simply emulating another virtual drive instead. The approach is said to increase transfer speed and allow the system to be reconfigured much more easily.
While it's tempting to look at the various backup approaches in terms of capacity, transfer speed, recovery time and other factors, the sad fact is that most enterprises will find they need a variety of solutions depending on the user. A low-cost system that combines the stability and capacity of tape, the speed and access of disk and the scalability of virtualization would be truly revolutionary.
If something like that comes along, we'll let you know.