How does one judge a glass of wine? There are a few tests, how it looks, smells and taste are the basic three. But as the wine is poured you may or may not know that your wine is made up of different varieties of grapes. A producer sits down and experiments with different percentages of grapes and this allows some creativity in making a better glass of wine for the consumer. Of course there are many more factors that play into this process but its by in large the same no matter what wine you enjoy. You enjoy the wine as a whole, a combination of things put together for you with out you having to know or even understand all that went into making that glass of wine.
When we talk to clients about their data backup strategy, we find a very similar process to that of wine making. The end user rarely knows all that goes in to creating a backup of their data and protecting it for them. They just enjoy the knowledge that their data is safe and will be there if they need to access it. But what we see in the making of the backup is a blend of technologies and a creative element that allows administrators some work around constraints like budget and man power.
As data evolves, we are seeing multiple layers of protection and depending on the severity of the data will determine the recovery point and recovery time as well as retention period. Backup technologies usually mean more than doing a bunch of incrementals and then a full off to disk pools and then tape. There are many different levels of protection that we can use.
Snapshots seem to be more common today than 5 years ago. They allow for a clean and consistent recovery point of a database or file system. But snapshots are used for more than just a quick backup, with writable copies we can quickly setup copies for test and dev environments and also rapidly deploy virtual images for desktops or servers. Snapshots are usually set to the same disk set that data is sitting on, and can be moved around via a vault technology or a mirror to another site. This can be used for long term storage if needed but typically snapshots are used for quick recoveries of less than 7 days. Snapshots are also vulnerable to data corruption. If a software bug comes in and corrupts data on the storage system, that can effect the snapshots and mirrors.
Backups are more traditional where the file system is scanned for changes and then those changes are sent off to a device where the data is stored until needed. In the past it has taken more time to backup file systems and as storage has gotten larger, those backup times grow longer. The technology has tried to keep up with adding larger backup servers and more tape drives allowing for more streams coming in. Now with the idea of using spinning disk for tape pools, we can backup a little quicker as the disk can write data faster than tape. There are many things that have evolved out of this technology, for example Long Term File System
or Hierarchical Storage Management
When clients are looking for strategies on protecting their data, they will use a combination of these techniques, and a mixture of both disks and tape to fully protect their environment. Depending o the data type, you may want to just use snapshots as the data changes rapidly and you do not need to restore from a week or a year ago. Snapshots are really useful in the case, and so is mirroring or even metro mirroring if the RTO is small enough. There are other factors such as Sarbanes-Oxley
that will require longer term recovery methods like backups.
Just like a great wine, there is fewer rules today and room for creativity in designing data protection. And just like wine, there are many consultants that will help you find a good balance of technology to match levels of protection with data. Spend the time looking at your protection schemes and see if there are any better ways of balancing this equation. Maybe, with the right planning, you will be able to enjoy a glass of wine instead of spending time recovering from a disaster.