Configuring the Storage

Currently, SFS, OBS, and EVS are supported for the server. The following table describes the differences of storage solutions. For details about how to configure local disks, see Physical Machine Environment Configuration.

**Table 1** Comparison among EVS, SFS, and OBS
Dimension	SFS	OBS	EVS
Concept	SFS provides on-demand high-performance file storage, which can be shared by multiple cloud servers. SFS is similar to a remote directory for Windows or Linux OSs.	OBS provides massive, secure, reliable, and cost-effective data storage for users to store data of any type and size.	EVS provides scalable block storage that features high reliability, high performance, and a variety of specifications for cloud servers to meet service requirements in different scenarios. An EVS disk is similar to a hard disk on a PC.
Data storage logic	SFS stores files and organizes them in a directory hierarchy.	OBS stores data as objects with metadata and unique identifiers. You can upload files directly to OBS. The system can generate metadata for files, or you can customize the metadata for files.	EVS stores binary data and cannot store files directly. To store files on an EVS disk, you need to format the file system first.
Access method	SFS file systems can be accessed only after being mounted to ECSs or BMSs through NFS or CIFS. You need to specify a network address or map it to a local directory for access.	Accessible through the Internet or Direct Connect (DC). You need to specify the bucket address for access and use transmission protocols such as HTTP and HTTPS.	EVS disks can be used and accessed from applications only after being attached to ECSs or BMSs and formatted.
Scenario	High-performance computing (HPC), media processing, file sharing, content management, and web services NOTE: HPC: High bandwidth is required for shared file storage, such as gene sequencing and image rendering.	Big data analysis, static website hosting, online video on demand (VoD), gene sequencing, and intelligent video surveillance	HPC, enterprise core cluster applications, enterprise application systems, and development and testing NOTE: HPC: High-speed and high-IOPS storage is required, such as industrial design and energy exploration.
Capacity	PB	EB	TB
Latency	3–10 ms	10 ms	Sub-millisecond
IOPS/TPS	10,000 for a single file system	Tens of millions	128,000 for a single disk
Bandwidth	GB/s	TB/s	MB/s
Data sharing	Yes	Yes	Yes
Remote access	Yes	Yes	No
Online editing	Yes	No	Yes
Used independently	Yes	Yes	No (EVS must work with BMS to store files.)

Using SFS for Storage

If you use SFS for storage, SFS Turbo file systems are recommended. SFS Turbo provides high-performance file storage on demand. It features high reliability and availability. It can be elastically expanded and performs better as its capacity grows. The service is suitable for a wide range of scenarios.

Create a file system on the SFS console. For details, see Creating an SFS Turbo File System. File systems and ECSs in different AZs of the same region can communicate with each other. Therefore, ensure that SFS Turbo and the server are in the same region.
Mount the created file system to the server. For details, see Mounting an NFS File System to ECSs (Linux).
Set automatic mounting upon restart on the server to prevent mounting loss. For details, see Mounting a File System Automatically.

Using OBS for Storage

Use OBS's parallel file system with obsutil for optimal performance. This system provides fast access to files, with low latency (milliseconds), high bandwidth (TB/s), and millions of IOPS. You can use obsutil, a command line tool for accessing OBS, to perform configurations in OBS, for example, creating a bucket, as well as uploading, downloading, and deleting files/folders. If you are familiar with command line interface (CLI), obsutil can provide you with better experience in batch processing and automated tasks.

Create a parallel file system on the OBS console. For details, see Creating a Parallel File System.
Download the corresponding obsutil to the ECS based on your OS and install it. For details, see Downloading and Installing obsutil.
Configure the OBS endpoint and AK/SK for obsutil to interconnect with OBS. You can use obsutil to perform operations on OBS buckets and objects only after obtaining the OBS authentication. For details, see Performing the Initial Configuration.
Use obsutil to upload and download OBS files in the server. For details about obsutil, see obsutil Introduction.

Using EVS for Storage

You can mount EVS data disks when creating a server. If the data disk space is insufficient after the server runs for a period of time, you can mount more data disks, which is known as post-mounting. In this case, you need to purchase EVS data disks and then mount them to the server. The following steps describe how to mount EVS disks in post-mounting mode.

Purchase an EVS data disk. Purchase a disk on the EVS console, select the AZ where the server node is located, set Attach to Server to Later, set Billing Mode to Yearly/Monthly or Pay-per-use, and set the disk size as needed.
- If the server resource type is set to BMS, the supported EVS disk types are subject to those displayed on the EVS console in the current AZ, and SCSI must be enabled in the advanced EVS configuration. A SCSI disk allows the server OS to directly access the underlying storage media and send SCSI commands to the disk.
- If the server resource type is set to ECS, the supported EVS disk types are subject to those displayed on the EVS console in the current AZ. VBS and SCSI EVS disk types are supported. You can choose whether to enable SCSI.
For details about EVS purchase parameters, see Purchasing an EVS Disk.
Figure 1 Buying a disk

Currently, an EVS disk cannot be mounted to the cloud server when it is being created. In this case, the system displays a message indicating that the Yearly/Monthly ECS has not been synchronized to the operations system. Please try again later. To address such problem, log in to the Huawei Cloud console, and choose Billing from the top menu bar. In the navigation pane on the left, choose Orders > Renewals. On the displayed page, check whether the ECS has been synchronized to the OS. If yes, set Attach to Server to Later.
After purchasing an EVS data disk, mount it to an existing server. You can choose a disk mounting mode.
If the server type is BMS or ECS, disks can be mounted on the server details page.

Mounting disks on the server details page:

Log in to the ModelArts console. In the navigation pane on the left, choose Lite Servers. Click a server name to access its details page. In the Disk tab, select an EVS data disk and set the mount point.

To detach a disk, click Detach on the server details page. System disks cannot be detached.

The mounted EVS data disk will not be automatically deleted when you unsubscribe from a BMS. You can mount the disk to other BMSs or delete it as needed.

If the server type is BMS, you can mount a disk on the BMS details page. For details, see Attaching Data Disks.

If the server type is ECS, you can mount a disk on the ECS details page. For details, see Attaching a Disk to an ECS.
After an EVS data disk is attached, it needs to be initialized. For details, see Initialization Overview.