Posted by Ryan Hulse at Scale Computing
Chances are you get to think about your storage on a regular basis because the pressure of needing more is always there.  If you are thinking about some of the following issues, it may be time to think about unified storage:
  • Are you looking to implement virtualization, or seeing pressure on your storage from over-exuberant virtualized growth?
  • Has disaster recovery, backup, or replication become a pain point?
  • Do you feel like you are wasting some of the unused storage sitting directly attached to some servers, while purchasing more and more disks for other servers.
  • Have past storage purchases resulted in the need to share data across two or more islands of storage?

If so, it may be time to adopt a unified scale-out storage system that combines SAN and NAS protocols in a single system with the capability to grow with you.

Direct attached storage, or DAS, is the most basic level of storage. DAS is directly connected to a single server and can only be accessed by that one server.  This may be fine for environments with no more than a couple servers where storage capacity requirements are fairly static.   The benefit of DAS is that it’s simple to deploy and has a lower initial cost than networked storage.  However, if your company anticipates rapid data growth and wants to get the most out their spending, consider a networked storage model because DAS is limited in its scalability and features.  Since resources are not shared beyond a single server in DAS, systems may use as little as half of their full capacity.  One DAS system might be completely full while the available space on other systems can’t be accessed.

Network attached storage, or NAS, shares file level data across servers and clients on a network. NAS is ideal for simple, cost-effective data sharing for multiple clients at the file level.  Network shares allow important data to be centrally managed and shared.  In contrast to DAS, the utilization rate with NAS can be high since storage is consolidated.  Also, IT administrators can centrally manage NAS systems, thus reducing management time and costs.  But for application data, not every application can use networked storage.  Many applications will only work with storage that is on the server where the application is installed.