# FileSystemAttributes

Properties that describe an existing EFS file system.

- Source: [`aws-efs/lib/efs-file-system.ts`](https://github.com/aws/aws-cdk/blob/v2.275.0/packages/aws-cdk-lib/aws-efs/lib/efs-file-system.ts#L349)

## Example

```ts
import * as iam from 'aws-cdk-lib/aws-iam';

const importedFileSystem = efs.FileSystem.fromFileSystemAttributes(this, 'existingFS', {
  fileSystemId: 'fs-12345678', // You can also use fileSystemArn instead of fileSystemId.
  securityGroup: ec2.SecurityGroup.fromSecurityGroupId(this, 'SG', 'sg-123456789', {
    allowAllOutbound: false,
  }),
});
```

## Properties

- `fileSystemArn`: string — The File System's Arn.

  **Default:** determined based on fileSystemId

- `fileSystemId`: string — The File System's ID.

  **Default:** determined based on fileSystemArn

- `securityGroup`: [ISecurityGroup](/cdk/api/v2/docs/aws-cdk-lib.aws_ec2.ISecurityGroup.html) (required) — The security group of the file system.