When it comes to IT data centers, it is apparent that there is a certain sensitivity associated with enacting changes, be it in the form of a system upgrade or software update. For an IT administrator who manages critical application servers such as Exchange and MS SQL, the golden rule is that any sequence of transactions has to be protected without any compromise. Also, for any transaction it is important that the parameters around consistency and uniqueness are maintained intact.
Any system or IT professional dealing with databases will understand how important it is to take a snapshot of a database. In this context, let me share my past experience when i handled exchange administration for a client, so that you might find it to be useful in case you ran into a similar situation.
A Short Story:
Once, when I had to recover my EDB at a designated point of time, I spent almost 2 hours with a failed turn out. It was very upsetting that I found the snapshot of the particular database was corrupted and not consistent. Luckily, I managed to recover the database somehow. After analysing the reason for the corruption, I cornered it as snapshot inconsistency. Possibly DB administrator must know what I mean here. The story ends here. However, this later sparked a curiosity in me as to how this could have been managed better and has helped us to add a suave feature to our product, namely ApplicationAware Backup. Vembu now uses this proprietary technology for ensuring that data snapshots are no longer corrupted.
ApplicationAware Backups – Vembu BDR:
When a backup snapshot is taken while a transaction is in progress, it leads to inconsistent state of backup. Also, the snapshot is of no use and the database cannot be mounted in case of exchange server crash. When the snapshot of transaction and backup is concurrent, Vembu BDR acts intelligently by using a simple logic. Snapshot for the backup will be taken only after that particular IOPs are frozen. This means that our backup engine waits for a while and lets the ongoing IO to be completed. Once the snapshot for backup is taken, the IOPs will be resumed automatically. That particular wait signal(protocol) is there to ensure that backups taken and configured, with ApplicationAware option enabled, have valid data sent to the backup server.
Perhaps, you have a question on what applications are being supported by this exciting feature in Vembu BDR! Well, we are supporting this for Exchange Server, SQL Server, and SharePoint backups! When you configure VMware or Disk image backups, you will have an option to configure and enable ApplicationAware backups. I’ll write more on this topic in my next blog about some best practices around it. Stay Tuned.
