Direct Attached Storage (DAS) is a storage that is in direct contact with an accessing computer. This kind of storage includes devices such as hard drives, external hard drives, and optical disk drives. The DAS Storage stays in the connection with one computer at a time.
A standard DAS environment is built with data storage device, which is generally set up with typical data storage device like collection of hard disks held tethered to single system directly via HBA (Host Bus Adapter). It is a primary characteristic of DAS Storage.
A typical DAS system is made of data storage device connected directly to computer via host bus adapter (HBA). Between those two points there is no network device such as hub, switch, router, etc. This is the main characteristic of DAS.
Tethering protocols for establishing DAS based connections include – Serial AT Attachment, USB / USB 3.0, ATA, Fiber Channel, eSATA, etc.
Advantages of Using DAS Storage
A DAS Storage is directly accessible by connected host machine and does not require any additional provisions to be accessed. Such storage is independent for resource sharing purposes. DAS is simple and organized owing to 1:1 association it shares with connected machine whereas storage is further divided on to other machines but logically. The physical connection remains only one directly taking place between storage device and computer.
Usage of DAS Storage
Direct attached storage is not fancy yet performance is not compromised with despite the minor investment it demands. However, it is also important that DAS Storage be used in the supported environment, which it is meant for originally. When storage components are chosen for virtual platforms, results in tradeoffs mostly. At the end, it is all about making right balance between cost, scalability, and performance aspects.
Preferable DAS Setup Environment
The implementation of a Direct Attached Storage means that your infrastructure options can limit hugely challenging the virtualization goals you may have had. DAS infrastructures depend upon the priorities of your setup however, it is of great importance to have high availability infrastructure along with the type of hypervisor installed and requirements that you have regarding scalability as well as failover.
DAS storage can act both as an internal and external storage for server. It can be setup with no as well as limited RAID array with maximum of two hosted ports, as this kind of storage can both be independent and standalone.
Other Side of DAS Storage Environment
DAS Storage is generally assigned to application server or database management systems or individual machine. This results in making data supervision for management purpose in future, an intractable process. A major drawback with DAS storage systems is that, in any case where addition of storage has to be done then it is not as direct as the attached storage. In order to make changes in the existing configurations, one needs to perform right from hardware system processing all backend applications that have been causing a downtime during their run. Moreover, a great deal of management overhead is demanded by the DAS type storage infrastructure as far as tasks like compliance and data backups are concerned.
Although, having a major set of setbacks associated, in comparison to other storage platforms and infrastructures, DAS storage still has lot to offer for users looking out for something that is affordable and decently stable storage