Everything You Need To Know About Storage Controllers before Buying Them

Buying a storage controller without knowing the details such as its functionality, speed and limitations can affect the overall performance of the data center. In this guide, we have tried to address all the minute details that would help you make a better buying decision.

Buy Storage Controllers for Servers,

What you will find in this post:

  • What are Storage Controllers and What They Do?
  • Types of Storage Controllers
  • Latest Storage Controllers in the Market
  • Best Brands to Consider when Buying Storage Controllers
  • Where to Buy Storage Controllers From?

What are Storage Controllers?

Think of a Storage Controller as an embedded processor chip that can do a wide variety of functions. It controls the flow of data between the storage devices and the operating system.

Mainly, it is a separate “space” that controls the volume exchange, provides an interface for SSDs, HDDs and other external mediums, and pre-caches active information for better flow of data.

Functions of Storage Controllers

All storage controllers have an input and output path for communicating between the storage network and the Direct Attached Storage (DAS).

A processor is present that handles the I/O functionality, managing the Redundant Array of Inexpensive Disks (RAID) and the volume being sent through the controller.

It also performs the complex tasks of cloning, taking snapshots, de-duplication and thin provisioning for efficient and loss-safe data access throughout the data center lifecycle.

Types of Storage Controllers

Storage controllers can be categorized as:

  • SATA Host Bus Adapters
  • Fibre Channel Host Bust Adapters
  • RAID Controller Cards
  • SAS Expander ICs

Factors that Affect Performance of Storage Controllers

Storage Controllers are the main facilitators when it comes to data center performance. In short, it can be said that the overall data flow is dependent on a storage controller’s performance.


The first factor that affects data center environment is its speed. Therefore, the top-most priority should be a high-speed storage infrastructure to process & perform functions involving data colocation.

Communication is another important factor. The controller needs to efficiently communicate with the attached disk drives for flawless data transfer. These drives need to be in unison with each other as the performance of the controller is directly proportional to the number of drives attached.

Data Bus Capacity:

In the old days, Solid State Drives used to surpass the speed of storage controllers creating a lag between the server and the storage units. Therefore, they had to be scaled down for matching speeds.

But now, as storage controllers are available with more capacity (up to 12Gbps), they can easily manage the data flow of multiple data storage units simultaneously – making the latency issue obsolete.

Thin Provisioning & Snapshots:

Thin provisioning, making of clones, and system snapshots made at every second can often clog the storage space, especially during high data processing times. The storage controllers have to pre-allocate space in the storage devices in this regard, but if more data needs to be stored, the pre-allocated space has to let go of the system image, thus slowing the overall performance.

Automated Tiering:

Another factor that affects the performance of Storage Controllers is automated tiering. It is a method by which seldom-used information is kept in slow speed drives, such as the hard drives. This is later shuffled when data fetching for that part becomes more active.

In automated tiering, the controllers have to analyze access patterns and statistics of various applications in order to move data. This decreases the quality of performance.

Pros and Cons of Different Types of Storage Controllers

Each Storage Controller has a processor that controls the flow of data, manages speed and carries out other tasks. These are the essentials we are talking about. Apart from these, most storage controllers are custom-designed by their manufacturers or purpose-built for a specific task, be exclusively available to a few servers as per company agreements or be open to all (white boxed).

All storage controllers have pros and cons; some have more speed while others have more reliability. Some even have enhanced heat resistance capacity. Vendors will only tell you about the pros of their storage controllers so it is up to you as a customer to evaluate the downsides and make a decision that best fits your needs.

Here we have explained the key characteristics for each type of storage controller that you should keep in mind when deciding what to buy:

Custom Designed:

Some Storage controllers have specific hardware that is made just for them. For example, Custom ASICs (Application Specific Integrated Circuits) or FPGAs (Field Programmable Gate Arrays) are common in custom controllers. These storage controllers may also include custom logic, processors and even custom software for their operations.


Performance and reliability are the major pros of custom-designed controllers. Performance comes from custom hardware data colocation, encryption, compression, and high-performance operations. Reliability comes from inbuilt error checking and reduction in the number of components.


The cons of custom-designed storage controllers include their cost and the duration it takes to build. Usually, it takes much longer to build a custom-designed storage controller because of the additional components they require.


Purpose-built storage controllers have an understanding of a particular hardware in the system. Common hardware is also integrated into the package.


This facilitates in:

  • Providing non-disruptive services
  • Scaling the system by adding more adapters


The biggest disadvantage of purpose-built storage controllers becomes apparent when newer generations of hardware are introduced. New processors require new motherboards and these may or may not be compatible with integrated storage controllers. It’ll take a substantial investment to acquire the new system.

Commodity Server-Based:

Commodity server-based storage controllers can run on a server through a driver. The server can be branded or white boxed – it doesn’t really matter.


The advantage of using a commodity server-based storage controller over others is its cost. The implementation of these servers is easy and connectivity can be done without going over your budget.


Commodity server-based storage controllers cannot be scaled easily. Moreover, upgrading, replacement of components and acquiring hardware support is another major problem.

Best Brands for Buying Storage Controllers

Some of the best Storage Controllers are provided by HP, IBM, Dell, Avago, Adaptec, LSI and other similar brands. The top-quality storage controllers are made by Adaptec & LSI.

These controllers include SAS/SATA Host Bus Adapters, Fibre Channel Cards, SAS Expander Cards, SAS/SATA RAID Controller Cards and other similar adapters that provide connectivity between storage mediums and servers.

When Do You Need A Storage Controller?

Storage controllers serve multiple purposes. If your enterprise has any of the following needs, you may be able to benefit from a good storage controller.

If the server needs:

  • Multiple storages, such as HDDs, SSDs & External Storages
  • More ports for connecting hard drives
  • High-speed data transfer between the system and the drives
  • Better volume management
  • Pre-caching of active data

We hope this information will help you make a better buying decision while searching for a Storage Controller. If you still need help, please contact us at (800) 821-3354 for professional advice.


  • I was just looking for how many types of Storage Controllers and what they are using for. Memory4less, you described nicely especially about the PROS and CONS.
    Thanks for sharing such a great advise and tips.


  • Phillip Corcoran

    Nice article post but do you know where can I buy passive storage controllers in Europe? Please mentioned their sites or store names?


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s