Disk Types and Performance¶
EVS disks are classified based on the disk I/O performance. EVS disks differ in performance and price. Choose the disk type most appropriate for your applications.
Application Scenarios¶
High I/O: This type of EVS disks delivers a maximum IOPS of 5,000 and a minimum read/write latency of 1 ms. They are designed to meet the needs of mainstream high-performance, high-reliability applications, such as enterprise applications, large-scale development and test environments, and web server logs.
Ultra-high I/O: This type of EVS disks delivers a maximum IOPS of 33,000 and a minimum read/write latency of 1 ms. They are excellent for read/write-intensive applications that require super-high I/O and bandwidth, such as distributed file systems in HPC scenarios or NoSQL/relational databases in I/O-intensive scenarios.
EVS Performance¶
EVS performance metrics include:
IOPS: Number of read/write operations performed by an EVS disk per second
Throughput: Amount of data read from and written into an EVS disk per second
Read/write I/O latency: Minimum interval between two consecutive read/write operations on an EVS disk
Single-queue access latencies of different types of EVS disks are as follows:
High I/O: 1 ms to 3 ms
Ultra-high I/O: 1 ms
Parameter | High I/O | Ultra-high I/O |
|---|---|---|
IOPS per GiB/EVS disk | 6 | 50 |
Max. IOPS/EVS disk | 5,000 | 33,000 |
Baseline IOPS/EVS disk | 1,200 | 1,500 |
Disk IOPS | Min. (5,000, 1,200 + 6 x Capacity) | Min. (33,000, 1,500 + 50 x Capacity) |
IOPS burst limit/EVS disk | 5,000 | 16,000 |
Max. throughput | 150 MiB/s | 350 MiB/s |
API name Note This API name indicates the value of the volume_type parameter in the EVS API. It does not represent the type of the underlying hardware device. | SAS | SSD |
Typical application scenarios | Mainstream applications requiring high performance and high reliability, such as large-scale development and test environments, web server logs, and enterprise applications. Typical enterprise applications include SAP applications, Microsoft Exchange, and Microsoft SharePoint. | Read/write-intensive applications that require ultra-high I/O and throughput, such as distributed file systems used in HPC scenarios or NoSQL and relational databases used in I/O-intensive scenarios. Typical databases include MongoDB, Oracle, SQL Server, MySQL, and PostgreSQL databases. |
Calculating Disk IOPS Limit¶
To calculate the IOPS limit of a disk, obtain the smaller value of the following two values:
Max. IOPS/disk
Baseline IOPS/disk + IOPS per GiB x Disk capacity
The following example uses an ultra-high I/O EVS disk with a maximum IOPS of 33,000.
If the disk capacity is 100 GiB, the disk IOPS limit is calculated as follows:
Disk IOPS limit = Min. (33,000, 1,500 + 50 x 100)
The disk IOPS limit is 6,500, the smaller value between 33,000 and 6,500.
If the disk capacity is 1,000 GiB, the disk IOPS limit is calculated as follows:
Disk IOPS limit = Min. (33,000, 1,500 + 50 x 1,000)
The disk IOPS limit is 33,000, the smaller value between 33,000 and 51,500.