Backing up SQL Azure
- by Herve Roggero
That's it!!! After many days and nights... and an amazing set of challenges, I just released the Enzo Backup for SQL Azure BETA product (http://www.bluesyntax.net). Clearly, that was one of the most challenging projects I have done so far.
Why???
Because to create a highly redundant system, expecting failures at all times for an operation that could take anywhere from a couple of minutes to a couple of hours, and still making sure that the operation completes at some point was remarkably challenging. Some routines have more error trapping that actual code...
Here are a few things I had to take into account:
Exponential Backoff (explained in another post)
Dual dynamic determination of number of rows to backup
Dynamic reduction of batch rows used to restore the data
Implementation of a flexible BULK Insert API that the tool could use
Implementation of a custom Storage REST API to handle automatic retries
Automatic data chunking based on blob sizes
Compression of data
Implementation of the Task Parallel Library at multiple levels including deserialization of Azure Table rows and backup/restore operations
Full or Partial Restore operations
Implementation of a Ghost class to serialize/deserialize data tables
And that's just a partial list... I will explain what some of those mean in future blob posts. A lot of the complexities had to do with implementing a form of retry logic, depending on the resource and the operation.
