What is the disk of the Aliyun service

Overview

The cloud server ECS disks can be used separately and in combination to meet the needs of different scenarios. Mainly divided into local SSD disk and cloud disk.

After reading this chapter, you can choose to use the appropriate data storage options, depending on your requirements.

For operational steps on how to mount a disk, see mount a data disk.

　　Cloud Disk

The cloud disk provides data block level data storage for ECS instances, and uses the distributed mechanism of three replicas to provide 99.9999999% data reliability guarantee for ECS instances.

According to the performance of different, the cloud can also be divided into ordinary cloud disk, efficient cloud disk and SSD and other types of cloud disk.

Common cloud disk for low I/O load scenarios, providing hundreds of IOPS of I/O performance for ECS instances.

High-efficiency cloud disk for moderate I/O load applications, providing an ECS instance with up to 3000 random IOPS storage performance.

SSD Cloud disks provide stable, high random IOPS performance for I/O intensive applications.

　　Local SSD Disk

The local SSD disk comes from the local storage of the physical machine where the instance resides. This class stores a block-level data access capability for instances with low latency, high random IOPS, and high throughput I/O capabilities.

　　Using local SSD disks, note the following issues:

Because storage space is from the server's local SSD disk, there is a single point of failure risk. It is recommended that data redundancy be done at the application layer to ensure the availability of data.

The CPU, memory, and the local SSD disk's lifting and lowering configuration are not supported after ordering.

　Disk parameter comparison

Parameters	SSD Cloud Disk	High Efficiency cloud disk	Common Cloud Plate	Local SSD Disk
Maximum capacity	32768 GB	32768 GB	GB	GB
Max IOPS	20000	3000	Hundreds	12000
Maximum throughput	256 MBps	MBps	20-40 MBps	250-300 MBps
Performance Calculation formula	iops=min{30* capacity, 20000} Throughput =min{50+0.5* capacity, 256}mbps	iops=min{1000+6* capacity, 3000} Throughput =min{50+0.1* capacity, 80}mbps	does not apply	does not apply
Access Time delay	0.5-2 ms	1-3 ms	5-10 ms	0.5-2 ms
Data reliability	99.9999999%	99.9999999%	99.9999999%	Physical machine reliability only, no SLA guarantee
API Name	Cloud_ssd	Cloud_efficiency	Cloud	Ephemeral_ssd
Price	1.0 Yuan/gb/months	0.5 yuan/gb/months	0.3 Yuan/gb/months	0.8 yuan/gb/months
Typical application Scenarios	I/O intensive applications Medium and large relational databases NoSQL Database	Small and medium sized databases Large scale Development test Web server Log	Scenarios that are not frequently accessed or have low I/O load	Hadoop, NoSQL and other distributed applications, the application itself has a very high reliability, the need for low latency, high I/O storage.

* The price of Hangzhou region in China is more detailed price

Below is a comparison of several important parameters for the cloud disk (excluding the local SSD disk).

Disk Performance test Methods

To test random write IOPS:

Fio-direct=1-iodepth=128-rw=randwrite-ioengine=libaio-bs=4k-size=10g-numjobs=1-runtime=1000-group_reporting- Name=/path/testfile

To test Random Read ioPS:

Fio-direct=1-iodepth=128-rw=randread-ioengine=libaio-bs=4k-size=10g-numjobs=1-runtime=1000-group_reporting- Name=/path/testfile

To test write throughput:

Fio-direct=1-iodepth=64-rw=randwrite-ioengine=libaio-bs=64k-size=10g-numjobs=1-runtime=1000-group_reporting- Name=/path/testfile

To test read throughput:

Fio-direct=1-iodepth=64-rw=randread-ioengine=libaio-bs=64k-size=10g-numjobs=1-runtime=1000-group_reporting- Name=/path/testfile