Performance metrics

There are three important metrics to evaluate the performance of RSSD UDisk:

• IOPS: the number of reads and writes per second.
• Throughput: read and write I/O traffic per second.
• I/O Latency: the time from the time when the I/O is submitted to the time when the I/O is completed.

Theoretically, the higher the IOPS and the higher the throughput, the better, and the lower the latency, the better.

IOPS

IOPS (Input/Output Operations Per Second) is a measurement method used to test the performance of computer storage devices such as hard disk (HDD), solid-state drives (SSDs), or storage area networks (SANs)), which can be regarded as the number of reads and writes per second. IOPS mainly includes four types of IOPS metrics according to different test tendencies: random read IOPS, random write IOPS, sequential read IOPS, and sequential write IOPS.

Througthput

Throughput is the average amount of data that a disk can successfully deliver per unit of time. The unit of throughput is usually expressed as megabytes per second (MB/s or MBps).

I/O Latency

I/O latency refers to the time it takes from the time an I/O request is sent to the time when the I/O request is completed.

Performance formula

Note: capacity refers to the size per RSSD UDisk, unit: GB

Relationship between RSSD UDisk performance and uhost instance

The I/O performance of a uhost instance is directly proportional to its CPU configuration, and the higher the number of uhost cores, the higher the RSSD UDisk IOPS and throughput.

• If the performance of the RSSD UDisk does not exceed the I/O storage capacity of the uhost instance, the actual storage performance is based on the performance of the RSSD UDisk
• If the performance of an RSSD UDisk exceeds the I/O storage capacity of the uhost instance, the actual storage performance is based on the storage performance of the uhost instance
• If uhost cpu configuration not in table below,the instance performance is the maximum performance that does not exceed the number of cores. For example, if the number of CPU cores is 50, the storage I/O performance is the same as that of 48 cores.