Function Storage Selection

This section describes the application scenarios and differences of the storage types supported by FunctionGraph.

Function Storage Comparison

FunctionGraph provides various storage types, including Elastic Cloud Server (ECS), Scalable File Service (SFS) Turbo, Object Storage Service (OBS), Ephemeral Storage, and Dependency. For details about the storage comparison, see Table 1.

**Table 1** Function storage comparison
Item	ECS	SFS Turbo	OBS	Ephemeral Storage	Dependency
Scenarios	Log and service file storage	Log and service file storage	Log and service file storage	Ephemeral service file storage	Release and deployment of public dependency libraries, runtime environments, and function extensions
Maximum space	Expandable	Scalable	Scalable	The default value is 512 MB. You can change the value to a maximum of 10 GB.	300 MB
Persistence	Persistent	Persistent	Persistent	Temporary	Persistent
Invocation sharing	Supported	Supported	Supported	Not supported	Supported
Storage content	Writable	Writable	Writable	Writable	Unwritable
Storage type	File system	File system	Object	File system	Code dependency archiving
Event source integration	Not supported	Not supported	Supported	Not supported	Not supported
Function access speed	Fast	Fast	Faster	Fastest	Faster
Billing	ECS Billing Overview	SFS Turbo Billing Overview	OBS Billing Overview	Free of charge when the disk size is less than or equal to 512 MB. For details, see Billing Item.	None

Storage Type Description

FunctionGraph supports the following storage types:

**Table 2** Storage types supported
Storage type	Description
ECS	ECS provides secure, high-performance, reliable, and easy-to-use file storage services by enabling the Network File System (NFS) service. FunctionGraph can seamlessly integrate with ECS, allowing functions to mount ECS shared directories. Once configured, functions can access the specified ECS shared directories the same way as accessing a local file system. An ECS directory can be configured as a shared file system via the NFS service, allowing functions to mount it for both reading and writing. This setup enables seamless scaling of compute resources as needed. You can configure user permissions to manage shared data resources. It is suitable for use cases that rely on existing ECS resources to rapidly enable lightweight data processing and file sharing, particularly when such workloads occur only occasionally. For details, see Configuring Disk Mounting.
SFS Turbo	SFS Turbo provides scalable, high-performance shared file storage (NAS) for shared file access from ECSs, Bare Metal Servers (BMSs), Cloud Container Engine (CCE) containers, and Cloud Container Instance (CCI) containers. FunctionGraph supports seamless integration with SFS Turbo, allowing functions to mount the SFS Turbo file system. After configuration, functions can access the specified file system the same way as accessing a local file system. The advantages of using SFS Turbo for function mounting are as follows: Ephemeral files can be stored in the SFS Turbo file system. Their size will not be limited by instance local disk space. Multiple functions can share an SFS Turbo file system. For details, see Configuring Disk Mounting.
OBS	OBS provides massive, secure, and cost-effective data storage for you to store data of any type and size. It is suitable for various scenarios, such as enterprise-level backup/archiving, video on demand (VoD), and video monitoring. FunctionGraph integrates with OBS via EventGrid (EG) triggers. You can customize functions to process OBS events. For example, you can invoke functions to process image or audio data and save results to various storage services. You only need to focus on writing function logic. The system will process massive data concurrently in real-time. For details, see EventGrid Trigger (OBS Application Service). You can also use the SDKs of OBS in the function code to read and write OBS.
Ephemeral Storage	FunctionGraph provides two ephemeral storage specifications: 512 MB and 10 GB. The lifecycle of the ephemeral storage is the same as that of the underlying function instance. If there are continuous requests, the instance remains. Therefore, the data previously stored on the disk is retained. If the function does not receive requests for a long time, the system will recycle the instance and the data on the disk will be lost. To set an ephemeral storage, contact technical support for authorization by submitting a service ticket.
Dependency	A dependency contains public libraries that support the running of function code. You can encapsulate the required public libraries into a dependency for easier management, sharing, and smaller deployment sizes. For details about the operation and restrictions of function dependencies, see Configuring Dependency Packages.