Direct Attached Storage
Direct attached storage is data storage that is connected directly to a computer such as a PC or server, as opposed to storage that is connected to a computer over a network. Sometimes known as DAS, direct attached storage has an important role to play in many organizations’ storage strategy because of the specific benefits that it offers.
How Does DAS Work
Almost every PC uses direct attached storage within the style of one or more internal storage drives, which can be traditional magnetic disk drives or faster solid state drives(SSDs), typically connected employing a Serial Advanced Technology Attachment (SATA) interface.
The defining feature of all direct attached storage is that it’s controlled by one computer to which is is attached. which means that the other computer that has to access the information stored on direct attached storage must communicate with the pc it’s attached to, instead of having the ability to access the info directly.
Many servers also are equipped with internal storage drives, which can be connected using SATA, faster Small automatic data processing system Interface (SCSI), Serial-Attached SCSI (SAS), or other high speed interfaces for better storage performance. But direct attached storage doesn’t should be connected to a computing system internally. It also includes external drives or drive enclosures (which may contain multiple drives), typically connected using USB, eSATA, SAS or SCSI to a private computing system.
Benefits of DAS
- High performance : Direct attached storage offers fast access to data because it’s attached to the pc that sometimes requires it. Network connectivity and congestion issues don’t directly affect direct attached storage.
- Easy to setup and configure: Computer systems are usually furnished with internal direct attached storage which is prepared to use immediately. External network attached storage can is sometimes “plug and play,” meaning that it are often used as soon because it is plugged in to an appropriate port like a USB port.
Low cost: Direct attached storage consists only of the device itself, plus any drive enclosure. meaning that it may be very cost effective compared to other storage solutions that need hardware and software to run and manage the storage devices.
Drawbacks of DAS
Limited scalability: Direct attached storage is difficult to scale because options are limited by the quantity of drive bays, the supply of external ports, and therefore the capacity of external direct attached storage devices. If internal direct attached storage must be upgraded this could involve shutting down the host computer during the upgrade.
Poor performance possible when data needs to be shared: Direct attached storage connected to a PC is slow to supply data to other computers on a network because performance depends partially on the resources of the host PC. Sharing data may impact on the performance of the host PC.
No central management and backup: Ensuring the info stored on direct attached storage is accessible and protected is way more complicated and customarily more costly than arranging redundancy and backups on networked storage devices, which can include their own management, RAID and backup software.
DAS Architecture
Direct attached storage architecture is extremely simple: PCs may access their own direct attached storage directly, or they’ll access data stored on direct attached storage connected to storage servers over a network. Direct attached storage is low cost, making it ideal for little businesses, which are unlikely to own rapidly expanding storage needs within the foreseeable future.
Other storage architectures like those used with network attached storage (NAS) and Storage Area Network (SAN) solutions are more complex, but offer benefits that direct attached storage cannot deliver
Performance Differences and Use Case: SAN, NAS, and DAS Storage
SAN
Storage area network solutions use a zealous high speed data network (usually supported fibre channel or iSCSI) to maneuver block-level data round the storage environment between servers and expensive — but fully featured — SAN storage arrays. The features that SAN arrays offer include deduplication, compression, encryption, and various availability services like backup and site mirroring.
SANs offer very high storage performance, reliability, and data availability, but because SAN storage arrays are very expensive and need management by a storage specialist they’re only suitable for big organizations with sizeable storage budgets and IT support teams.
NAS
Network Attached Storage consists of hardware (usually a storage appliance), storage devices like hard drives, and software which manages the storage devices, arranges data backups and redundancy (usually through some RAID configuration), and provides networked access (as well as restricting access) to those devices (often through Active Directory).
The computer hardware is optimized for managing and providing access to data, which implies that NAS usually offers far better performance than direct attached storage in environments where data has to be shared by variety of various users. NAS can even be scaled up very quickly just by adding more NAS devices to the network.
DAS
Direct attached storage generally offers high storage performance to the pc system which it’s directly attached to, because the information is found near the system’s RAM and processor. and since it’s not suffering from network congestion, and since it can profit of fast computer bus interfaces like SAS and SATA.
The DAS is attached to a storage server then data will still must travel over a network to the pc system to request the info from the storage server, which implies that it’ll still be subject to network congestion.
