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What Makes SAN Storage a Better Fit for Enterprises Over DAS


If you are an enterprise, you know that performance and reliability are crucial to your business. SAN storage is one of the technologies that can help provide those high levels of performance and reliability. The question is: should your business consider going with SAN or stay with DAS?

SAN storage system extends the capabilities of traditional servers while supplying enterprise-class built-in features such as disaster recovery and mission-critical availability.

What makes SAN storage stand out as a better choice than DAS? In this article, we will look at why these two technologies are different and compare how they each fit enterprise requirements.

Key Criteria to Consider Before Choosing Between Two Solutions:

Deciding which is right for your business depends on the following factors.

  • Capacity: The amount of data you need to store
  • Scalability: How much do you expect your data to grow in the next 5 to 10 years
  • Downtime: How much downtime can your business tolerate, and what effect will it have if your business is left without its mission-critical data.
  • Backup and Recovery: How do you propose to back up your systems, and what kind of data do your systems host? For example, media and apps, or databases?
  • Performance: What is the size of your organization, and how many people will be accessing or collaborating on the data at once?
  • Budget: How much can you spend?
  • Resources and Staff: Do you have qualified staff to manage your systems?

DAS - Direct-Attached Storage

DAS is a storage type that is directly connected to the hosts. It is the most basic, low-cost solution that requires lesser maintenance and is easy to deploy. DAS is used in many IT infrastructures as DAS storage units can accommodate multiple disks in a single closure. However, DAS has a certain limit after which it cannot scale enough to meet the greater flexibility requirements of certain enterprises. This is especially true for those businesses that are expecting to see considerable growth over a short period.

Advantages of DAS

The primary advantage of DAS is performance as the storage systems are directly connected to the host systems. These systems have low latency and thus have a good enough performance for traditional workloads. They can be a cost-effective solution for businesses that don't have complex storage requirements.

Best Use Case: DAS is an ideal choice for businesses with simple storage requirements that do not have to share and access data over the network and have a non-growth budget and minimal IT support to handle their storage systems.

Disadvantages of DAS

DAS does not have storage connectivity over the network and does not allow multiple users to connect to the storage simultaneously from remote locations and multiple devices. Additionally, DAS is limited by its design and has very limited expandability owing to the limited number of connections and drives a host can support.

Worst Use Case: DAS is not a good choice for businesses that are growing quickly, need to scale quickly, share across distances and collaborate or support multiple users and activities at once.

SAN - Storage Area Network

SAN is a high-performing datacenter oriented storage solution that can handle complex storage requirements. San provides block-level access to the host device and is reliable and scalable storage for various enterprise workloads.

SAN is a more sophisticated storage option typically used in virtual computing environments in data centres with enterprise workloads. SAN storage uses these protocols to connect to the hosts:

  • SCSI
  • ISCI
  • Fibre Channel

Many top-tier companies like IBM, DELL, StoneFly, and HP actively provide SAN solutions for various enterprise needs.

Advantages of SAN

SAN is mainly targeted toward enterprise-grade and mission-critical workloads. With block-level access, enterprises can eliminate the need for local storage and create storage environments that support data access to all connected devices over the network. SAN is flexible and provides virtually unlimited scalability compared to DAS, making it a good choice for enterprise storage needs.

Best Use Case: SAN is best for large-scale enterprise organizations that need block-level data sharing of mission-critical files with high-performance data transfer through Fiber Channel.

Disadvantages of SAN

The biggest drawback of SAN is the complexity. Even a basic SAN setup requires dedicated hardware and software solutions with a high-performing network architecture that can utilize SAN FC or iSCSI to its full potential.

Worst Use Case: SAN is a very sophisticated solution only suited to enterprise-level large-scale computing needs. A small-scale organization with a limited budget would be better off with a DAS or, at most, NAS storage.

Why is SAN better in Terms of Performance and Scalability?

DAS has storage arrays directly connected to servers, whereas SAN works through connecting servers and arrays through a network switch. Each device within the network can access the SAN storage arrays. This is why SAN has an edge against DAS storage regarding flexibility and scalability.

Since SAN allows storage access to multiple hosts through a single network port, it is very flexible. The arrays can then be clustered together for scalability. Regardless of how many drives are in the array or how many arrays are clustered together, every device connected to the switch can access the storage.

SAN also uses the Fibre Chanel, which is used for high-performance block-level data transfer. Although Fibre Chanel is common, modern devices also use the iSCSI protocol.

SAN solutions also use intelligent disk arrays with additional features like local and remote replication, snapshots, virtualization, and highly resilient architecture that eliminates single points of failure.

On the other hand, the DAS storage is connected in a 1:1 ratio with the servers. This means limited scalability and no flexibility when upgrading the storage. Each array is limited to its physical capacity and cannot be expanded further.

If you need to expand the storage, you will require complex RAID configurations, tinkering with the software for workarounds and even pay for additional hardware.

Consider that if your storage has to be assigned to a single host and you are not expecting this configuration to change any soon, DAS might be the lowest cost option. However, if you have to distribute the data between multiple hosts, if you want your data to be highly available, or if you have high-performance requirements that cater to block-level storage, SAN is a much more viable and flexible option.

Bottom Line

Choosing the best storage option for your business comes down to deciding which criteria are most important. Once you know which factors are essential to your business operations, you can find the storage option to fit your particular needs.



George Williams, Senior Technical & Product Marketing Specialist, StoneFly Inc.


George Williams has over 13 years of experience in the data storage, backup and disaster recovery, air-gapping, immutability and archiving markets. A true geek with love for ease and simplicity in data storage, George has been working for StoneFly Inc. for over a decade. Ever since StoneFly started shipping products since 2006, George has been working to ensure that technical information is relayed in a simple and effective way to customers and targeted audience. George helps curate content and works with numerous publishers and technology blogs to spread awareness and knowledge of data storage technology.

Published Thursday, June 23, 2022 7:31 AM by David Marshall
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