Architecture and terms of NAS - Apsara File Storage NAS - Alibaba Cloud Documentation Center

This topic describes the terms that are used in Apsara File Storage NAS (NAS). To better understand and use NAS, we recommend that you read this topic.

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 systems 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 Container Service for Kubernetes (ACK) clusters. The following figure shows the relationships between compute nodes and a NAS file system. 文件存储NAS工作架构

Alibaba Cloud terms

Term	Definition	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 Mount a file system across accounts and regions.
region	A geographic location where Alibaba Cloud data centers are deployed. Examples: China (Hangzhou) and China (Beijing).	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 access from an on-premises data center to a NAS file system is relatively complex. For more information, see Use CEN to mount a NAS file system across VPCs in the same region.
zone	An isolated location in a region where the power supply and network are independent. Examples: 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 the vSwitch must reside in the same zone as the NAS file system. 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.

NAS-specific terms

Term	Definition	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 ideal file storage applications rather than network disks. NAS file systems cannot be accessed by using RESTful APIs.
storage plan	A billing method that is used to offset the storage usage fees of 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. Only one storage plan can be attached to a General-purpose NAS file system at a time. If you delete a General-purpose NAS file system, the attached storage plan is detached. You can attach the storage plan to another General-purpose NAS file system. However, the new file system must have the same storage class and reside in the same region as the file system that you delete. 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 to which a storage plan is attached, the storage plan can still be attached to a Server Message Block (SMB) file system. A storage plan is related to the storage class of a file system. For example, if you delete a Capacity NAS file system to which a storage plan is attached, the storage plan cannot be attached to a Performance NAS file system. If you delete a Performance NAS file system to which a storage plan is attached, the storage plan cannot be attached to a Capacity NAS file system.
mount	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 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	An endpoint of a NAS file system in the classic network or in 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 defines the permissions to access a file system by using mount targets. You can add rules to a permission group to specify the authorized IP addresses and the corresponding read and write permissions on the file system.	Each mount target must be bound to only one permission group. However, each permission group can be bound to multiple mount targets.
Capacity NAS file system	A type of General-purpose NAS file systems. Capacity NAS file systems are suitable for cost-sensitive file sharing workloads that require moderate latency, such as database backup, log storage, Windows user directory, and Linux home directory.	The storage capacity of a Capacity NAS file system can be automatically expanded. The maximum storage capacity is 10 PiB.
Premium NAS file system	A type of General-purpose NAS file systems. Premium NAS file systems are suitable for latency-sensitive file sharing workloads that require low latency, such as container data persistence, AI training data storage, manufacturing simulation, and genetic computing.	The storage capacity of a Premium NAS file system can be automatically expanded. The maximum storage capacity is 1 PiB.
Performance NAS file system	A type of General-purpose NAS file systems. Performance NAS file systems are suitable for latency-sensitive file sharing workloads that require low latency, such as Linux or Windows applications for enterprises, container persistent volumes (PVs), web content management, and genetic computing.	The storage capacity of a Performance NAS file system can be automatically expanded. The maximum storage capacity is 1 PiB.
Infrequent Access (IA) storage class	A low-cost data storage pool for General-purpose NAS file systems. The IA storage class is suitable for storing data that is accessed less than three times per month.	For General-purpose NAS file systems (Capacity Premium, and Performance), you can use the lifecycle management feature to migrate infrequently accessed data to the IA storage class. The migrated data remains in the same namespace as that before the migration and can be accessed at any time. You can retrieve the data in the IA storage class to a General-purpose NAS file system. You cannot write data directly to the IA storage class.
Network File System (NFS)	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 is specified when the file system is created and cannot be changed after the file system is created. General-purpose NAS file systems support both NFSv3 and NFSv4.0. You can specify the protocol version when you mount a file system. In most cases, NFSv3 provides better performance than NFSv4.0. 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 NFSv4.0 to enable the file locking feature. Extreme NAS file systems support only NFSv3. The protocol of a file system cannot be changed after the file system is created. You can create a file system with a different protocol and migrate data from the original file system to the new file system.
Server Message Block (SMB)	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 a 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.