Terms - Product Introduction| Alibaba Cloud Documentation Center

Architecture of NAS

NAS is a distributed file sharing solution that provides high scalability, reliability, and performance. NAS allows you to migrate business data from on-premises storage solutions to Alibaba Cloud without the need to modify your application code. Each NAS file system can be mounted on thousands of compute nodes, such as Elastic Compute Service (ECS) instances and Alibaba Cloud Container Service for Kubernetes (ACK) clusters. The relationship between computing nodes and NAS modules is shown in the following figure. 架构图

Terms in Alibaba Cloud


Term	Description	Usage notes
UID	The ID of the Alibaba Cloud account. The account ID is a string of numbers. You can view the account ID on the Account Management page of the Alibaba Cloud Management Console.	In most cases, you must mount a NAS file system on a compute node of the same Alibaba Cloud account. A cross-account mount is complex. For more information, see Enable a cross-account mount for a file system.
region	A geographic area where a data center resides. Example: China (Hangzhou) and Germany (Frankfurt).	The region where a file system resides cannot be modified after the file system is created. In most cases, you must mount a NAS file system on a compute node in the same region. A cross-region mount or an access from on-premises storage solution to a NAS file system is relatively complex. For more information, see Mount a file system across VPCs or regions.
zone	Isolated locations in a region where the power supply and network are independent. Example: Hangzhou Zone B and Frankfurt Zone A.	To achieve optimal performance, the compute node and the mount target must belong to the same VSwitch and reside in the same zone. You can mount General-purpose NAS file systems on compute nodes in different zones. However, we recommend that you mount Extreme NAS file systems on compute nodes in the same zone.
VPC	A logically isolated network. You can connect two virtual private clouds (VPCs) by using Cloud Enterprise Network (CEN).	A network environment is a prerequisite for compute nodes to access NAS file systems. We recommend that you use a VPC rather than the classic network for better user experience.

Terms in NAS


Term	Description	Usage notes
file system	A place where files are stored. A file system can be mounted on a compute node by using a mount target. The data and metadata in the file system are stored in the traditional directory tree structure. A file system supports simultaneous access from hundreds of compute nodes for data sharing and highly concurrent read and write operations.	NAS file systems are more applicable to applications than network disks. RESTful APIs are not supported.
storage plan	A billing method for General-purpose NAS file systems. This billing method allows you to plan your NAS resources and enjoy discounts.	The capacity of a file system is not limited by the storage plan that is attached to the file system. The maximum capacity of a Capacity NAS file system is 10 PiB. The maximum capacity of a Performance NAS file system is 1 PiB. A General-purpose NAS file system can be attached only one storage plan at a time. If you delete a General-purpose NAS file system, the storage plan is detached. You can then attach the storage plan to another General-purpose NAS file system. This file system must be of the same type and reside in the same region as the deleted file system. A storage plan is unrelated to the protocol that is used by a file system. For example, if you delete a Network File System (NFS) file system that is attached a storage plan, the storage plan can still be attached to a Server Message Block (SMB) file system. A storage plan is related to the type of a file system. For example, if you delete a NAS Capacity file system that is attached a storage plan, the storage plan cannot be attached to a NAS Performance file system. If you delete a NAS Performance file system that is attached a storage plan, the storage plan cannot be attached to a NAS Capacity file system.
mount	Mount is the process to connect a compute node to a NAS file system. After a NAS file system is mounted on a compute node, the compute node can access data in the file system.	You can mount a NAS file system on an Elastic Compute Service (ECS) instance by using the CLI. You can also mount a NAS file system on a container cluster (for example, a Kubernetes cluster) by using the console or configuration file.
mount target	A connection point of a NAS file system in the classic network or a VPC. Each mount target is displayed as a domain name.	You can create a maximum of two mount targets for a General-purpose NAS file system and only one mount target for an Extreme NAS file system. A mount target can be concurrently accessed by hundreds of compute nodes in the same network. To mount a file system on a compute node, the mount target of the file system must reside in the same network as the compute node. A compute node in a VPC can access only the mount targets in the VPC. A compute node in the classic network can access only the mount targets in the classic network.
permission group	A group that is used to configure the access permissions of a mount target. You can add rules to a permission group to specify the IP addresses and the corresponding read and write permissions on the file system.	Each mount target must be attached only one permission group. However, each permission group can be attached to multiple mount targets.
NAS Capacity	A type of General-purpose NAS file systems. NAS Capacity file systems are applicable to scenarios that require high cost efficiency and large capacity.	NAS Capacity file systems support the auto scaling feature. The capacity of a NAS Capacity file system can be a maximum of 10 PiB.
NAS Performance	A type of General-purpose NAS file systems. NAS Performance file systems are applicable to scenarios that require high concurrency and high throughput.	NAS Performance file systems support the auto scaling feature. The capacity of a NAS Performance file system can be a maximum of 1 PiB.
NFS protocol	A software protocol that is used to mount a NAS file system on a compute node. The NFS protocol is applicable to Linux clients and most containers.	The protocol of a file system cannot be modified after the file system is created. General-purpose NAS file systems support both NFSv3 and NFSv4. You can specify the protocol when you mount a file system. In most cases, NFSv3 provides better performance than NFSv4. We recommend that you use NFSv3. If multiple compute nodes need to modify a file at the same time, you must mount the file system by using NFSv4 to enable the file locking feature. Extreme NAS file systems support only NFSv3. The protocol of a file system cannot be modified after the file system is created. You can create a file system of another protocol and migrate data from the original file system to the new file system.
SMB protocol	A software protocol that is used to mount a NAS file system on a compute node. The SMB protocol is applicable to Windows clients and Windows containers.	None.
POSIX-based APIs	A set of standard interfaces that are used to access files in a Linux operating system. You can call the POSIX-based APIs by using a programming language in applications to manage files.	Linux applications also use POSIX interfaces to manage on-premises files. Therefore, if you migrate on-premises files to NAS file system, you can access the files without the need to modify the application code. To achieve optimal performance of NAS file systems, we recommend that you increase the concurrency of your applications and increase the block size for read and write operations.