Disk Types
EVS disks are classified, by performance, into the following types: Extreme SSD, Ultra-high I/O, General Purpose SSD, and High I/O. EVS disks differ in performance and price. Choose the disk type most appropriate for your applications.
Extreme SSD EVS disks use congestion control algorithms for Remote Direct Memory Access (RDMA) deployments. An extreme SSD disk can reach up to 1,000 MiB/s of throughput and offer extreme low single-channel latency.
Performance Metrics
- 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
Specifications
EVS disk types and performance
|
Parameter
|
Extreme SSD
|
Ultra-high I/O
|
General Purpose SSD
|
High I/O
|
|---|---|---|---|---|
Max. capacity (GiB) |
• System disk: 1,024 • Data disk: 32,768 |
• System disk: 1,024 • Data disk: 32,768 |
• System disk: 1,024 • Data disk: 32,768 |
• System disk: 1,024 • Data disk: 32,768 |
Short description |
Superfast disks for workloads demanding ultra-high bandwidth and ultra-low latency |
High performance disks excellent for enterprise mission-critical services as well as workloads demanding high throughput and low latency |
Cost-effective disks designed for enterprise applications with medium performance requirements |
Disks suitable for commonly accessed workloadsf |
Typical workloads |
• Database workloads
• AI workloads |
• Transcoding services • I/O-intensive workloads
• Latency-sensitive application
|
• Enterprise OA • Medium-scale development and test environments • Small- and medium-sized databases • Web applications • System disks |
Common development and test environments |
Max. IOPSa |
128,000 |
50,000 |
20,000 |
5,000 |
Max. throughputa (MiB/s) |
1,000 |
350 |
250 |
150 |
Burst IOPS limita |
64,000 |
16,000 |
8,000 |
5,000 |
Disk IOPSc |
Min. [128,000, 1,800 + 50 x Capacity (GiB)] |
Min. [50,000, 1,800 + 50 x Capacity (GiB)] |
Min. [20,000, 1,800 + 12 x Capacity (GiB)] |
Min. [5,000, 1,800 + 8 x Capacity (GiB)] |
Disk throughputb (MiB/s) |
Min. [1,000, 120 + 0.5 × Capacity (GiB)] |
Min. [350, 120 + 0.5 × Capacity (GiB)] |
Min. [250, 100 + 0.5 × Capacity (GiB)] |
Min. [150, 100 + 0.15 × Capacity (GiB)] |
Single-queue access latencyd (ms) |
Sub-millisecond |
1 |
1 |
1 to 3 |
API namee |
ESSD |
SSD |
GPSSD |
SAS |
NOTE:
a: The maximum IOPS, maximum throughput, and burst IOPS limit are all calculated based on the sum of read and write operations. For example, maximum IOPS = read IOPS + write IOPS.
b: Take ultra-high I/O for example: The baseline throughput is 120 MiB/s. The throughput increases by 0.5 MiB/s for every one GiB added until it reaches the maximum throughput 350 MiB/s.
c: Take ultra-high I/O for example: The baseline IOPS is 1,800. The IOPS increases by 50 for every one GiB added until it reaches the maximum IOPS 50,000.
d: A single queue indicates that the queue depth or concurrency is 1. The single-queue access latency is the I/O latency when all I/O requests are processed sequentially. The values in the table are calculated with 4 KiB data blocks.
e: 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.
f: High I/O disks (except for those created in dedicated storage pools) are HDD-backed disks. They are suitable for applications with commonly accessed workloads. The baseline throughput of a high I/O disk is 40 MiB/s per TiB, and the maximum throughput of a high I/O disk is 150 MiB/s. If your applications have high workloads, it is recommended that you choose the disk types with higher specifications. Such types of disks are SSD-backed disks.