More on Virtual Tape

Last week I talked about virtual tape solutions. On Monday HDS released the news that they're reselling Diligent's VTL solution. From memory, when I last saw this about 12 months ago, it was a software only solution for emulating tape, sure enough that's still the same. Probably the more useful thing though is ProtecTIER, which scans all incoming data and proactively compresses the incoming stream by de-duplicating the data. The algorithm relies on a cache map of previously scanned data held in memory on the product's server, with a claimed supported capacity of 1PB raw, or 25PB at the alleged 25:1 compression ratio.

As Hu Yoshida referenced the release on his blog, I asked the question on compression. 25:1 is a claimed average from customer experience, some customers have seen even greater savings.

So, my questions; what is performance like? What happens if the ProtecTIER server goes titsup (technical expression)? I seem to remember from my previous presentation on the product that the data was stored in a self referential form, allowing the archive index to be easily recreated.

If the compression ratio is true and performance is not compromised, then this could truly be a superb product for bringing disk based backup into the mainstream. Forget the VTL solution; just do straight disk based backups using something like Netbackup disk storage groups and relish in the benefits!!!