What Is EVS?

Overview

Elastic Volume Service (EVS) offers scalable block storage for cloud servers. With high reliability, high performance, and a variety of specifications, EVS disks can be used for distributed file systems, development and test environments, data warehouses, and high-performance computing (HPC) applications. Cloud servers that EVS supports include Elastic Cloud Servers (ECSs) and Bare Metal Servers (BMSs).

EVS disks are sometimes just referred to as disks.

EVS Advantages

EVS has the following advantages:

Various disk types
EVS provides a variety of disk types for you to choose from, and EVS disks can be used as data disks and system disks for serverss. You can select an appropriate disk type that best suits your budget and service requirements.
Elastic scalability
The EVS disk capacity ranges from 10 GiB to 32 TiB. When it no longer meets your needs, you can expand the disk capacity up to 32 TiB in increments of 1 GiB, without interrupting your applications.

Besides the disk capacity limit, the additional space you can add cannot exceed the remaining quota. You can increase the quota if the remaining quota is insufficient.
High security and reliability
Data protection functions, such as backups and snapshots, safeguard the disk data, preventing incorrect data caused by application exceptions or attacks.
Real-time monitoring
On Cloud Eye, you can monitor the disk health and operating status at any time.

Differences Among EVS, SFS, and OBS

There are currently three types of storage available for you to choose from: EVS, Scalable File Service (SFS), and Object Storage Service (OBS). See their differences in the following table.

**Table 1** Differences among EVS, SFS, and OBS
Service	Overall Introduction	Typical Application Scenarios	Storage Capacity
EVS	EVS provides scalable block storage that features high reliability, high performance, and a variety of specifications for servers.	Enterprise office applications Development and testing Enterprise applications, including SAP, Microsoft Exchange, and Microsoft SharePoint Distributed file systems Various databases, including MongoDB, Oracle, SQL Server, MySQL, and PostgreSQL	EVS disks start at 10 GiB and can be expanded as required in 1 GiB increments to up to 32 TiB.
SFS	SFS provides completely hosted shared file storage for cloud servers. Compatible with the Network File System (NFS) protocol, SFS is expandable to petabytes and seamlessly handles data-intensive and bandwidth-intensive applications.	HPC scenarios, such as gene sequencing, animation rendering, and CAD/CAE File sharing Media processing Content management and web services Offline file backup	SFS storage capacity is available on demand and can be expanded to 10 PB at most.
OBS	OBS provides cloud storage for unstructured data, such as files, pictures, and videos. With multiple options for migration to the cloud, OBS provides low-cost, reliable storage access for massive data and supports online multimedia processing.	Enterprise backup and archive Big data analysis Enterprise cloud box Static website hosting Cloud-native applications	OBS has limitless storage capacity, and storage resources are available for linear and nearly infinite expansion.