ExaGrid's Eye on Deduplication

The word scalability is often applied broadly. Scalability in backup simply means that when your data grows you can add more capacity.

 What are all the questions you need to ask?

1. Does the additional capacity just plug in and virtualize itself into the existing capacity?  Most vendors have simple plug and play inclusion of additional capacity.
2. Can all the capacity be managed from a single console? The answer is typically yes within a single scalable system.  However, is the answer still yes if you max out a system and add a second system?
3. Do I need to change anything in my existing backup application or does it all work together seamlessly? How much work is there: none, 15 minutes or hours?
4. When I add capacity am I just adding more disk or am I adding more performance?  This may be the most important question because if your backups are 5TB and they grow to 10TB and all you add is disk capacity, then your backups will slow down and explode your backup window. You need to add processor, memory, bandwidth and disk with data growth to ensure that the backup window does not expand.
5. How big can the current system scale before I need a second system and how many systems can I have in a group? Knowing this ensures you have plenty of room to grow without having to trade out vendors.

 If you go to disk and have a backup window of 6 hours and you double your data you don't want the backup window to go 12 hours. By adding all four resources in tandem with data growth you ensure a fixed backup window versus an expanding backup window. Make sure the system at 10TB has twice the memory, processor, bandwidth and disk of the system at 5TB. Otherwise, you are putting 10TB through the same resources you were putting 5TB through...and as they say in high tech...there is no free lunch.

Bill Andrews is President and CEO of ExaGrid Systems a company that provides fast, low cost and scalable disk-based backup with data de-duplication solutions.