HBA/RAID controller

Native and Maximum supported disks

There is a concept in RAID controller, that are Native Supported Disks and Maximum Supported Disks.

• Native supported disk # means the number of disks that can be direct connected to the RAID controller usinb brakeout cable
• Maximum supported disks # means when to use of port expanders such as Intel RES2SV240

Controller Interface

The RAID controller has an interface that connects to the storage drive and an interface that connects to the

CPU. The drive interfaces are Serial Attached SCSI (SAS), Serial Advanced Technology Attachment (SATA),

and Non-Volatile Memory Express (NVMe). NVMe is a communication protocol designed for flash storages

that use Peripheral Component Interconnect Express (PCIe) for connectivity.

Storage drive side interface	Communication band	Theoretical throughput	Effective throughput (90%)
SATA 6G	6 Gbps	572 MiB/s	515 MiB
SAS 12G	12 Gbps	1,144 MiB/s	1,030 MiB/s
NVMe Gen3	8 Gbps x4	3,756 MiB/s	3,380 MiB/s
NVMe Gen4	16 Gbps x4	7,512 MiB/s	6,760 MiB/s

CPU side Interface	Number of lanes	Communication band	Theoretical throughput	Effective throughput (90%)
DMI Gen3	x4	8 Gbps x4	3,756 MiB/s	3,380 MiB/s
PCIe Gen3	x8	8 Gbps x8	7,512 MiB/s	6,760 MiB/s
PCIe Gen3	x16	8 Gbps x16	15,024 MiB/s	13,520 MiB/s
PCIe Gen4	x8	16 Gbps x8	15,024 MiB/s	13,520 MiB/s
PCIe Gen4	x16	16 Gbps x16	30,048 MiB/s	27,040 MiB/s

*The theoretically achievable throughput is calculated by subtracting 1.54% redundancy with 128b/130b coding.

The actual achievable throughput can be estimated by multiplying this value by 0.90.

Expected Performance by RAID type

RAID level	Type	Random read	Random write	Sequential read transfer performance	Sequential write transfer performance
RAID0	Stripe	1	1	N x SR	N x SW
RAID1	Mirror	1	2	N x SR	N x SW / 2
RAID10	Mirror + Stripe	1	2	N x SR	N x SW / 2
RAID5	Single Parity	1	4	N x SR	(N-1) x SW
RAID6	Double Parity	1	6	N x SR	(N-2) x SW
Where, N: Number of drives, SR: Single read performance, SW: Single write

Performance Index - Throughput / Transaction

• Throughput [MiB/s] - Data transfer amount per second (in megabytes)
• Transaction [IO/s] - IO processing per second
• Latency [ms] - Average response time (in milliseconds)

"Data Throughput” value used to load profiles with sequential access pattern, while “Transaction Rate”

value used to load profiles with random access pattern. Throughput and transaction are in direct

proportion to each other and can be calculated mutually using the follow

• Data throughput [KiB/s] = Transaction rate [IO/s] x Block size
• Transaction rate [IO/s] = Data throughput [KiB/s] / Block size [KiB]