Dear Nirvanix Team:

One huge feature that I think would help you to set yourself apart from Amazon and other up-and-coming storage providers is the ability for our client-side software applications to do delta level backups and process them with server-side assistance.  Please allow me to explain:

Many of us are using the service to do backups of our computers or to store archived data or even to store huge graphics files, video, and other items that can take a LOOONG time to upload.  So, what I would find HUGELY attractive to your service is functionality that is similar to rsync where it uses both the server-side and client to pass delta information efficiently.

If you could provide us with the ability to upload a huge file (or even small files) and we could easily pass back block-level deltas and upload only the portions that the server-side needs and then you patch them.. well I think I would come down there and give each of you a great big KISS!

I'm going to guess that many others would use this feature and because Amazon and others don't offer it.. well.. you'll be WAAAAAY ahead of the game and offering all of us a service that we can all use!  Besides, who wants to pay for all that bandwidth when we don't really need to?

You guys are doing a great job and I think this type of feature will be a win-win for everyone.  Keep up the excellent work!

Sincerely,

Joshua

 We have this functionality already available.  Look in the documentation for "Partial File Update" for a full description of how to use it along with some examples.  The basic implementation lets you treat the upload the same way you would as partial file upload via http but instead upload just a portion of the new file that has changed.  The original idea was spawned for exactly the reason you describe.  We wanted to make sure differential backups could be performed on a file without sending the whole file.  The difficult part of course is performing the diff and knowing what has changed without keeping two copies at the client but I think that is for those who are in the backup space to know far better than we will.

Please let me know if you have any questions on how this is implemented or if you have any other questions.  You can find a C# example of the Partial File Update which shows how to change a file here:

http://developer.nirvanix.com/files/folders/csharpsnippets/default.aspx

Regards,
    Barry R.
 

Barry:

I was aware of the upload partial file but as a noob c# programmer it was determine what portion to upload!?  I mean.. I can see how your software could combine the data file to "update it" with the latest bits but how do we know what bits to send?  I think we need to see this all work from start to finish with a code example from you guys as it's not making sense to me.  Is this something y'all can do for us!?

I think others would concur.  Thanks!

- Joshua

 This, I feel, is one of the toughest problems facing backup companies.  How to quickly, reliably get a difference between files and know only what needs to be updated without duplication of data and letting it happen quickly.  Unfortunately, due to the raw difficulty mixed with our lack of expertise in this area, a sample probably wouldn't help much.  We can certainly determine if a whole file is different but trying to determine if portions of a file is truly a difficult task.

Just to get you started you could look at some binary difference code combined with the update code.  I'm afraid we don't have any more of an idea than anyone else of what the best way to do this is and it would be a work of innovation and not just something we can create an example for.

Take a look at this for a binary diff: http://www.codeproject.com/KB/recipes/diffengine.aspx 

Best Regards,
     Barry R.

I understand the difficulty Barry.  I appreciate you taking the time!