Production SAN environments are becoming more and more prevalent in businesses across the board from SMB all the way to large enterprise. A SAN gives you the ability to have a central pool of storage that is high speed and modular to an extent. You can also set up SAN to SAN replication to get a copy of that data from your main production SAN array to another offsite. So in the event the main array or data center goes down you have another array ready to roll with your data on it. I am going very high level here so you SAN administrators don’t despair with how “little” I dive into your wheelhouse. Another level of protection a SAN array can bring is called snapshots. A snapshots is an image based capture of the array at a given point in time, so if something happens after a snapshot occurs you can go back to that snapshot and recover or restore from that snapshot. Pretty nifty and consolidated.
Here comes the “but”. Your SAN infrastructure is the most expensive disk that you have in your racks. It is also the most important disks in your racks. These are the awesome arrays that you fought for from management for 3 years to get. But what is a SAN for? To house your business data making it easier, faster, cleaner to access by users and so forth. What is the lifeblood of a business? Its data. So no matter how awesome your SAN arrays are, if that data gets lost or corrupted in any way it kind of defeats the purpose of an awesome storage array.
So what am I saying? You need another layer of protection outside of the array/s to protect your data. Snapshots are great, but do you want to keep snapshots on a SAN that if a disaster occurs and I lose my SAN then my snapshots are gone as well. I am not saying don’t use snapshots I am saying let’s not put everything in one basket. SAN to SAN replication is fantastic and is needed, but you cannot rely on that as your Disaster Recovery Plan alone. Why? Because if something happens to the communication between the SANs and the data gets corrupted, now you have corrupted data that you have to figure out how to work through as well as get your business back up and running. Again this is why you need another layer to “back” you up.
Take your SAN to SAN replication and make as lean as you can because that is your high speed, expensive disk for your production environment. Then add in a backup environment to cover yourself for those events when you need to do massive recoveries or just need to recover a database or an email. The SAN environment and your backup environment can work hand in hand, both replicating data offsite so in the event there is some type of a disaster, you have solid faith in your plan that you can get your business back up and running and still have all of your data.
SAN environments and backup environments work by themselves, but they work even better together.