CPFS protocol service scenario questions - Cloud Parallel File Storage

What protocols does a CPFS protocol service support?

CPFS protocol services support only NFSv3.

Are CPFS protocol services free of charge?

General-purpose protocol services are free. Cache protocol services are a paid feature that provides memory cache capabilities and extra bandwidth. For pricing details, see Pricing.

What are the applicable scenarios for CPFS protocol services?

Use CPFS protocol services for Kubernetes-based high-performance computing and video rendering. For scenarios that have high I/O requirements or depend on MPI-IO, such as electronic design automation (EDA) chip design, meteorology, and oil industry computing, access the CPFS file system by using the CPFS-POSIX client.

What are the differences between the CPFS-POSIX client and the CPFS-NFS client?

Differences	CPFS-POSIX client	CPFS-NFS client
How to use	Install the POSIX client on a Linux-based ECS instance and add the instance to a CPFS-POSIX client cluster.	Install a lightweight NFS client on a Linux-based ECS instance and run the `mount` command to mount the CPFS file system.
Required mount target	POSIX mount target.	Filesets or export directories of an NFS protocol service.
Support for Kubernetes	CSI hostpath driver.	CSI NFS driver and CSI hostpath driver.
Quorum node	Three low-specification ECS instances are created as quorum nodes within your Alibaba Cloud account. These nodes serve as client management nodes. Standard ECS instance fees apply.	No quorum node required.
Accessible space	Entire CPFS file system directory tree.	Directory tree under the mount target.
Performance	Highest data and metadata I/O performance. Best suited for small files smaller than 100 KiB. See Specifications.	Lower data and metadata IOPS than the CPFS-POSIX client due to NFS protocol limits. Best suited for files of 100 KiB or larger. See Specifications.
Access control	NFSv4 ACL	NFSv4 ACL-based read-only and read/write control by IP address and CIDR block.
Recommended scenarios	ECS	Kubernetes clusters, ACK clusters, elastic container instances (ECIs), special OS versions, and video rendering.

Do CPFS protocol services depend on POSIX mount targets?

No. CPFS protocol services and POSIX mount targets are independent access channels. To access a CPFS file system only through the NFS client, create a protocol service and configure the export directory without creating a POSIX mount target. Delete unused POSIX mount targets as needed.

Why does the protocol service feature fail to enable?

The protocol service feature requires CPFS V2.3.0 or later. To check the version of a CPFS file system, see the "View the version number of a file system" section in View the details of a file system.

What is the difference between exporting filesets and directories?

Filesets and directories provide the same I/O access performance. However, filesets support additional features such as data flow, which combined with protocol services can address more business scenarios. Create a fileset and export it as a data access point for optimal functionality.

How do I change the specifications of a protocol service?

Perform the following operations based on the change type:

Change the protocol service type from general-purpose to cache
Important
- Direct switching between general-purpose and cache protocol services is not supported. Delete the existing protocol service and create a new one of the target type. This process causes service interruption. Plan a maintenance window before proceeding.
- Regenerate the export folder after the change.
1. Delete the general-purpose protocol service
  
  On the Protocol Service tab, find the target protocol service. Click Delete in the Actions column, and then click OK.
2. Create a cache protocol service
  
  For more information, see the "Create a protocol service" section in Manage protocol services.
Change the protocol service type from one cache type to another
1. On the Protocol Service tab, find the target protocol service.
2. Click Modify in the Actions column and select another cache type.
3. After the modification is complete, click OK.

Can I change the bandwidth of a protocol service?

Yes. Perform the following operations based on the service type:

General-purpose

The bandwidth of general-purpose protocol services matches the CPFS file system bandwidth. To increase the bandwidth, use one of the following methods:
- Scale up the CPFS file system. For more information, see Scale up a CPFS file system.
- Change the protocol service specifications. For more information, see the Change the protocol service type from general-purpose to cache section.
Cache type

Cache protocol services support multiple bandwidth specifications. Select the appropriate bandwidth based on your business needs. For more information, see the "Modify a protocol service" section in the Manage protocol services topic.

Note
The modification takes 2 to 5 minutes to take effect.

How do I monitor the performance of protocol services?

To configure threshold-triggered alert rules for monitoring metrics, use CloudMonitor. For more information, see Configure a basic alert rule.

To configure alert rules based on computing results of multiple metrics, use Hybrid Cloud Monitoring. For more information, see Configure an advanced alert rule.

Does deleting a protocol service delete the data stored in CPFS?

No. Deleting a protocol service does not affect the data stored in CPFS. However, all connections through the deleted protocol service are terminated. To access the original data, create a new protocol service or POSIX mount target.