You can use File Storage NAS (NAS) volumes in Container Service for Kubernetes (ACK) clusters. This topic describes the features, types, scenarios, limits, and billing of NAS volumes.
Description
NAS is an Alibaba Cloud service that provides file storage for compute nodes such as Elastic Compute Service (ECS) instances, Elastic High-Performance Computing (E-HPC) clusters, and ACK clusters. NAS is a distributed file storage system 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 automatically 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.
Storage types
NAS provides the following file system types: General-purpose Performance NAS file systems, General-purpose Premium NAS file systems, General-purpose Capacity NAS file systems, standard Extreme NAS file systems, and advance Extreme NAS file systems. For more information about how to select a NAS file system, see How do I select file systems?
Scenarios
The following table describes the operations that you can perform on a NAS volume to meet your business requirements.
Business requirement | References |
(Recommended) Use Container Network File System (CNFS) to manage NAS file systems | You can use CNFS to manage the lifecycles of NAS file systems. This ensures data security, enables data sharing, and accelerates access to NAS file systems. CFNS provides distributed caching services that support multiple parallel connections, allow you to read and write data cache at the client side, and support the Lease mechanism. These features can accelerate read and write operations on NAS file systems. This way, NAS file systems can provide a user experience similar to local file systems. For more information, see the following topics: |
(Recommended) Use CNFS to persist application data | For more information, see the following topics: |
(Recommended) Use CNFS to automatically expand NAS volumes | You can use expansion policies to enable auto expansion for NAS volumes when the capacity usage exceeds specific thresholds. For more information, see Use CNFS to automatically expand NAS volumes. |
Accelerate data access in parallel computing scenarios | You can create distributed cache pools based on the memory of compute nodes. The cache pools can automatically scale in or out based on the computing demand to accelerate access to hot data in NAS volumes. We recommend that you use CNFS to accelerate data access in AI training and genomics computing scenarios. For more information, see Enable the distributed caching feature of the CNFS client. |
Persist application data without using CNFS | For more information, see the following topics: |
Set quotas for NAS volumes without using CNFS | You can set quotas on the directories of NAS volumes to manage the storage space of NAS volumes. For more information, see Expand a NAS volume. Note If your NAS file system is managed by using CNFS, no additional configuration is required. |
Limits
NAS is a shared storage service. A persistent volume claim (PVC) that is used to mount a NAS file system can be shared among pods.
You cannot use the Container Storage Interface (CSI) plug-in to mount Server Message Block (SMB) file systems.
We recommend that you use the NFSv3 file sharing protocol.
You can mount a NAS volume only to ECS instances in the same virtual private cloud (VPC) as the NAS file system.
General-purpose and Extreme NAS file systems have different limits such as the limits on mounting connectivity, the number of file systems, and file sharing protocols. For more information, see Limits.
Before you use NAS volumes, we recommend that you update the CSI plug-in to the latest version.
After a mount target is created, wait until the mount target changes to the Available state.
Do not delete the mount target of a NAS file system before you unmount the NAS file system. Otherwise, an operating system hang issue may occur.
Billing
For more information about the billing of NAS, see Billing of General-purpose NAS file systems.