The SAS interface offers considerable advantages for modern workloads with their SCSI standard. In contrast, NVMe leverages the PCIe standard and multiple bus lanes to unlock the full potential of Solid State Drives (SSD) Technology. It delivers faster data as compared to SATA and SAS SSD.
NVMe and SAS are all storage interfaces to connect drives to a computer. This section will cover the differences between SAS vs. NVMe SSD, and how they are relevant in 2023.
SAS SSD vs. NVMe SSD
When selecting a storage system, it is important to analyze the need, budget and requirements before choosing an interface. Here is the complete difference between NVMe SSD vs. SAS SSD to help you make an informed decision.
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Feature
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SAS
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NVMe
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Speed
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Up to 12 Gb/s
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Up to 6 GB/s
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Form Factor
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2.5 and 3.5 inch
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U.2 (2.5 inch) and M.2
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Storage
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From 256 GB to 2 TBs and more
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Management Interface
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SES
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NVMe-MI
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Energy Consumption
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Varies with capacity and workload
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Flexibility
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Designs that will be useful in the future
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There is a risk of future-proofing design options
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Life
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5 – 7 years
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Up to 10 years
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Price
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$500 – $1000
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$500 – $2000
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SAS vs. NVMe: Architecture
NVMe connects directly with the CPU via a PCIe bus and smooth data path. It eliminates the need for Host Bus Adapters (HBA) and significantly reduces latency i.e. 0.07 μs. In contrast, the SAS SSD connects to the CPU via the HBA. This adds an extra break in the data transfer path, increasing latency i.e. 0.3 μs and limiting performance.
The architecture design of NVMe ensures faster data transfer speed with lower latency, while the SAS SSD does not.
SAS vs. NVMe: Speed
A high-performing SAS SSD utilizes SCSI protocol to deliver a read and write speed of 12 Gbps (GigaBits Per Second). Whereas, enterprise-grade NVMe SSDs use multiple PCIe lanes to achieve read speeds of 6 GBps (GigaBytes Per Second), and write speed of 7 GBps. The speed difference between SAS SSD vs. NVMe SSD affects not only the data throughput but also the performance of the overall system.
The speed of NVMe is many times higher than SAS SSD, but there are many other factors to consider before choosing one.
SAS vs. NVMe: Size/ Form Factor
SAS SSD comes only in 2.5 and 3.5 inches, while the NVMe SSD comes in U.2 (2.5 inch) and M.2 sizes which is equivalent to a gum stick. The advantage of the M.2 form factor is that it can reduce the size of new-generation laptops significantly.
The different form factors between NVMe vs. SAS highlight their flexibility, scalability and accessibility in various enterprises.
SAS vs. NVMe: Storage Arrays
The SAS architecture provides the accessibility to create large storage arrays with numerous SAS drives. Whereas, a single storage array can include up to dozens of SAS drives. However, it depends on the controller to maintain the connection between storage devices and CPU.
Similarly, NVMe also enables the creation of storage arrays, but the cost per gigabyte is considerably higher than SAS SSDs. Here, the SAS SSD has an upper hand over NVMe in data centers or mass storage enterprises purely on cost-effectiveness.
SAS vs. NVMe: Reliability and Management Interface
When dealing with a storage system, it must be reliable and easily manageable. Fortunately, both NVMe and SAS SSD support hot swapping, and come in flexible form factors and management interfaces like NVMe-MI and SES respectively.
SCSI Enclosure Services (SES) provides in-band management that monitors device health, temperature, and other vital functions. In contrast, NVMe Management Interface (NVMe-MI) is built over SES but provides both in-band and out-band management. This includes a unified management console, which simplifies device management.
Here is a complete management interface difference between SAS vs. NVMe in tabular format.
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Features
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SES
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NVMe-MI
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Management protocol
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SCSI
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NVMe
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Management capabilities
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In-band only
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In and out-band
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Management console
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Unified
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Operating System (OS) specific
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Supported OS
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Multiple
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Single
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SAS vs. NVMe: Bottleneck
A bottleneck occurs in storage arrays when the combined bandwidth of the drives exceeds the controller's maximum bandwidth. This happens when multiple NVMe or SAS drives combine their bandwidth and surpass that of a single drive.
For example: If a controller's bandwidth limit is 5000 MB/s and drive's combined bandwidth is 20,000 MB/s. The controller can only process at a rate of 5000 MB/s, even if the combined bandwidth is higher. That said, using an NVMe storage array is useless until the system controller is capable of high data transfer speed.
SAS vs. NVMe: Energy Consumption
There are several factors that affect the power consumption of a storage system. Drive type, capacity, performance, workload and idle power consumption. So, high capacity and performance drives will consume more power and vice versa.
SAS vs. NVMe: Life
SAS drives can last an average of 5 – 7 years, while NVMe drives can last up to 10 years. However, there are some additional factors that can cause a faster decline in the storage drivehealth.
- Frequent data writes
- High temperature
- Drive Type
Some drives might have features to prevent wear and tear like wear-leveling and over-provisioning. To check the lifespan of an SSD, check the Total Bytes Written (TBW) rating from the storage manufacturer datasheet and divide it by your expected data writes per month. It will give you a rough estimate of how long the drive will last.
SAS vs. NVMe: Price
SAS SSDs and expanders are cost-effective and straightforward, but NVMe utilizes switch-based scaling, which adds cost and complexity to achieve higher performance.
The cost of SAS SSD ranges from $300 – $1000, but it could vary depending on brand, capacity and form factor. In contrast, NVMe's cost ranges from $500 – $2000 also depending on brand, capacity and form factor.
SAS vs. NVMe: Which Drive is Best For Your Organization?
It is important to evaluate the requirements, needs and budget before you buy a storage drive for any system. Briefly, SAS drives provide cost-effective data storage solutions, while NVMe is faster, and more reliable, but less cost-effective. Computing Worlds offers a wide range of the best SAS and NVMe solid state drives for sale online:
Popular SAS SSDs
Popular NVMe SSDs
Frequently Ask Questions:
Will NVMe Work over SAS?
No, NVMe will not work over SAS, because they are different technologies with different communication protocols and interfaces.
Which Is Faster, SAS or NVMe?
NVMe is faster than SAS drives, because they are a new technology that incorporates the PCIe lanes and can transfer data at a speed of 4 GB/s theoretically, and more.
Which Is Best for Data Centers, SAS or NVMe?
SAS is best for the data centers because it provides a low cost per gigabyte of data transferred as compared to NVMe.
This brings us to the end of our comprehensive drive comparison SSDs, NVMe vs. SAS. SAS drives have been providing fast-speed data storage for decades. They are designed keeping in mind the needs of companies with large storage requirements. That said, NVMe has been designed to optimize performance and latency in personal computers and laptops, which makes it the storage of the future. However, the NVMe requires many changes within the storage system for optimization which makes it less cost-effective than SAS drives.
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