Storage Performance Reference Guide: Interconnect Maximum Effective Data Rates

When designing and evaluating performance for networked storage, there is an entire chain of interconnects to consider along the data path. From the interface of the hard drive(s) storing the data to the PCIe connection of the individual client connection’s network interface (and many points along the way), each connection in the path can have its own impact on the ultimate throughput of pushing (or pulling) the bits from point A to point B.

Without going into a complex discussion on performance design (that’s something we can tackle in a future blog series), we simply wanted to offer a few handy tables we at iXsystems use as references internally that layout data rates for the most common storage interfaces and interconnects.

These tables list the maximum effective data rates, in a single data flow direction, for various data interconnect protocols.¹ They can also be used to help quickly convert between Megabytes (or Mebibytes) per second to Gigabits per second (and vice-versa).

Feel free to bookmark this for future reference (or even print it out and tack it to your wall as some of us have). We hope this is helpful. If there is anything else you’d like to see, feel free to post a comment.

¹ Attempts have been made to exclude physical link encoding overheads where appropriate.

Maximum Effective Data Rate (One Direction)

PCI Express 3.0& NVMe Mebibytes per second (MiB/s) (1024^2 Bytes) Megabytes per second (MB/s) (1000^2 Bytes) Gigabits per second (Gb/s) (1000^3 Bits) Notes x1 939 985 7.9 x2 1,878 1,969 15.7 NVMe M.2 (M+B Key) x4 3,756 3,938 31.5 NVMe M.2 (M Key) and U.2 x8 7,512 7,877 63 x16 15,024 15,754 126

Maximum Effective Data Rate (One Direction)

SAS-3(12 Gb/s) Mebibytes per second (MiB/s) (1024^2 Bytes) Megabytes per second (MB/s) (1000^2 Bytes) Gigabits per second (Gb/s) (1000^3 Bits) x1 1,144 1,200 9.6 x4 4,578 4,800 38.4 x8 9,152 9,600 76.8

Maximum Effective Data Rate (One Direction)

SAS-2 &SATA 3.0 (6 Gb/s) Mebibytes per second (MiB/s) (1024^2 Bytes) Megabytes per second (MB/s) (1000^2 Bytes) Gigabits per second (Gb/s) (1000^3 Bits) x1 572 600 4.8 x4 2,289 2,400 19.2 x8 4,576 4,800 38.4

Maximum Effective Data Rate (One Direction)

Ethernet Mebibytes per second (MiB/s) (1024^2 Bytes) Megabytes per second (MB/s) (1000^2 Bytes) Gigabits per second (Gb/s) (1000^3 Bits) 1 GbE 119 125 1.0 10 GbE 1,192 1,250 10.0 25 GbE 2,980 3,125 25.0 40 GbE 4,768 5,000 40.0 100 GbE 11,920 12,499 100.0

Maximum Effective Data Rate (One Direction)

Fibre Channel Mebibytes per second (MiB/s) (1024^2 Bytes) Megabytes per second (MB/s) (1000^2 Bytes) Gigabits per second (Gb/s) (1000^3 Bits) 8 Gb 787 825 6.6 16 Gb 1,575 1,652 13.2 32 Gb 3,150 3,303 26.4

And, may your storage always be as fast as your slowest interconnect! 😉

All the best,

The iXsystems Storage Team