You can use Apsara File Storage NAS (NAS) volumes in Container Service for Kubernetes (ACK) clusters. This topic describes the features, types, use scenarios, limits, and billing rules of NAS volumes.

Features

NAS is a cloud service that provides a file storage solution for compute nodes, such as Elastic Compute Service (ECS) instances, nodes in Elastic High-Performance Computing (E-HPC) clusters, and nodes in ACK clusters. NAS is a distributed file storage solution that provides shared access, scalability, high reliability, and high performance.

NAS uses Portable Operating System Interface of UNIX (POSIX)-based APIs and is compatible with native operating systems. NAS provides shared access, ensures data consistency, and implements mutual exclusion by using locks. NAS provides scalable file systems and allows simultaneous access to a NAS file system from multiple ECS instances. The storage capacity of a NAS file system scales in or out when you add or remove files. NAS provides shared data sources for workloads and applications that run on multiple ECS instances or servers.

NAS file system types

NAS provides the following file system types: General-purpose NAS Capacity, General-purpose NAS Performance, and Extreme NAS. For more information, see NAS types.

Use scenarios

The following table describes the operations that you can perform on a NAS volume to meet your business requirements.

Business requirement References
Store application data
Use quotas to configure resource allocation and improve overall resource utilization

For more information, see Set quotas on the subdirectories of NAS volumes.

Manage NAS file systems Using Container Network File System (CNFS) greatly simplifies the procedure of mounting NAS volumes. Compared with using persistent volume claims (PVCs), you do not need to frequently switch between the NAS console and ACK console when you use CNFS to mount a NAS volume. This reduces the operations to mount a NAS volume and improves the success rate of mounting a NAS volume. For more information, see Use CNFS to manage NAS file systems.
Automatically expand NAS volumes. Using expansion policies to enable auto expansion of NAS volumes when the capacity usage exceeds specific thresholds. For more information, see Use CNFS to automatically expand NAS volumes.
Create dynamically provisioned NAS volumes to share NAS file systems Using the Container Storage Interface (CSI) plug-in provided by Alibaba Cloud to create multiple persistent volumes (PVs) that are used to mount the same NAS subdirectory. For more information, see Use CNFS to share a dynamically provisioned NAS volume.

Limits

  • NAS is a shared storage service. A PVC that is used to mount a NAS file system can be used by multiple pods.
  • Do not delete the mount target before you unmount the NAS file system. Otherwise, the operating system hang may occur.
  • After a mount target is created, wait until the state of the mount target changes to Available.
  • We recommend that you use NFSv3.
  • Before you use NAS volumes, we recommend that you upgrade the CSI plug-in to the latest version.
  • General-purpose and Extreme NAS file systems have different limits on mounting scenarios, the number of file systems, and file sharing protocols. For more information, see Limits of Apsara File Storage NAS.

Billing

For more information about the billing rules of NAS, see NAS billing.