Hi,

I work freelance as an IT consultant and am busy implementing an onsite backup system for one of my clients. They are a video production company and use an XSan system onsite with approximately 4TB of redundant storage available via fibre channel. We need to implement a cost-effective system for the backup of their video production data from Final Cut (and a host of other applications).

After some extensive research I found QRecall and have been evaluating the software on our systems here. I have a lot of experience with backup software on various platforms and have always been an enormous fan of the very few products which implement any form of binary delta-copy on incremental backups. Since in this case, we need to backup colossal amounts of data on a nightly basis, QRecall seems perfect for the task, since an approach using what is essentially delta patching has the potential to massively reduce the backup window.

Having looked at the technical specs for the software, I noticed that the maximum archive size is only 2TB. Given that we need to incrementally backup a 4TB volume I suspect this is very sadly going to be a deal breaker for us? I just wanted to check that nothing has changed in newer builds of the software? If not, I assume given the engineering complexity of upping this limit that there is nothing you could do for us anytime soon?

My client's server is running OS X Tiger and we will be backing up to an 8TB disk array, so an upper archive size limit of at least this much would be essential really (to maintain a decent backup history). The backup disk array will be connected via Infiniband to a specialist RAID card so performance in that respect should not be a problem.

Sorry if this is a little outside your intended market for QRecall, any help you can provide would be *very* gratefully received. QRecall seems an extremely innovative product and I would very much like to be able to recommend it to my clients both for this, and a multitude of other applications!

Best regards,
James

Hello James,

James Molesworth wrote:Having looked at the technical specs for the software, I noticed that the maximum archive size is only 2TB.

That's correct.

The 2TB limit was set empirically. Theoretically, QRecall could create archives that are much larger, but testing showed that the overhead of searching for duplicate data in a 2TB archive overwhelms the capture process.

Sorry if this is a little outside your intended market for QRecall, any help you can provide would be *very* gratefully received. QRecall seems an extremely innovative product and I would very much like to be able to recommend it to my clients both for this, and a multitude of other applications!

It is a little outside the limits of QRecall at the moment. I have plans for a 64-bit version of QRecall that will surpass the 2TB hurdle, but that won't happen anytime soon.

For QRecall to work efficiently, you might consider if the source material could be subdivided into 1 or 2 TB sections that could be captured to separate archives. That would probably work quit effeiciently, but would obviously entail more user intervention.