Copy data to or from a file system by using Azure Data Factory or Azure Synapse Analytics

APPLIES TO: Azure Data Factory Azure Synapse Analytics

This article outlines how to copy data to and from file system. To learn more, read the introductory article for Azure Data Factory or Azure Synapse Analytics.

Supported capabilities

This file system connector is supported for the following capabilities:

Supported capabilities	IR
Copy activity (source/sink)	① ②
Lookup activity	① ②
GetMetadata activity	① ②
Delete activity	① ②

① Azure integration runtime ② Self-hosted integration runtime

Specifically, this file system connector supports:

• Copying files from/to network file share. To use a Linux file share, install Samba on your Linux server.
• Copying files using Windows authentication.
• Copying files as-is or parsing/generating files with the supported file formats and compression codecs.

Prerequisites

If your data store is located inside an on-premises network, an Azure virtual network, or Amazon Virtual Private Cloud, you need to configure a self-hosted integration runtime to connect to it.

If your data store is a managed cloud data service, you can use the Azure Integration Runtime. If the access is restricted to IPs that are approved in the firewall rules, you can add Azure Integration Runtime IPs to the allow list.

You can also use the managed virtual network integration runtime feature in Azure Data Factory to access the on-premises network without installing and configuring a self-hosted integration runtime.

For more information about the network security mechanisms and options supported by Data Factory, see Data access strategies.

Getting started

To perform the Copy activity with a pipeline, you can use one of the following tools or SDKs:

• The Copy Data tool
• The Azure portal
• The .NET SDK
• The Python SDK
• Azure PowerShell
• The REST API
• The Azure Resource Manager template

Create a file system linked service using UI

Use the following steps to create a file system linked service in the Azure portal UI.

1. Browse to the Manage tab in your Azure Data Factory or Synapse workspace and select Linked Services, then select New:

   • Azure Data Factory
   • Azure Synapse

   

2. Search for file and select the File System connector.

   

3. Configure the service details, test the connection, and create the new linked service.

   

Connector configuration details

The following sections provide details about properties that are used to define Data Factory and Synapse pipeline entities specific to file system.

Linked service properties

The following properties are supported for file system linked service:

Property	Description	Required
type	The type property must be set to: FileServer.	Yes
host	Specifies the root path of the folder that you want to copy. Use the escape character "" for special characters in the string. See Sample linked service and dataset definitions for examples.	Yes
userId	Specify the ID of the user who has access to the server.	Yes
password	Specify the password for the user (userId). Mark this field as a SecureString to store it securely, or reference a secret stored in Azure Key Vault.	Yes
connectVia	The Integration Runtime to be used to connect to the data store. Learn more from Prerequisites section. If not specified, it uses the default Azure Integration Runtime.	No

Sample linked service and dataset definitions

Scenario	"host" in linked service definition	"folderPath" in dataset definition
Remote shared folder: Examples: \\myserver\share\* or \\myserver\share\folder\subfolder\*	In JSON: \\\\myserver\\share On UI: \\myserver\share	In JSON: .\\ or folder\\subfolder On UI: .\ or folder\subfolder

Example:

{
    "name": "FileLinkedService",
    "properties": {
        "type": "FileServer",
        "typeProperties": {
            "host": "<host>",
            "userId": "<domain>\\<user>",
            "password": {
                "type": "SecureString",
                "value": "<password>"
            }
        },
        "connectVia": {
            "referenceName": "<name of Integration Runtime>",
            "type": "IntegrationRuntimeReference"
        }
    }
}

Dataset properties

For a full list of sections and properties available for defining datasets, see the Datasets article.

Azure Data Factory supports the following file formats. Refer to each article for format-based settings.

• Avro format
• Binary format
• Delimited text format
• Excel format
• JSON format
• ORC format
• Parquet format
• XML format

The following properties are supported for file system under location settings in format-based dataset:

Property	Description	Required
type	The type property under location in dataset must be set to FileServerLocation.	Yes
folderPath	The path to folder. If you want to use wildcard to filter folder, skip this setting and specify in activity source settings. You need to set up the file share location in your Windows or Linux environment to expose the folder for sharing.	No
fileName	The file name under the given folderPath. If you want to use wildcard to filter files, skip this setting and specify in activity source settings.	No

Example:

{
    "name": "DelimitedTextDataset",
    "properties": {
        "type": "DelimitedText",
        "linkedServiceName": {
            "referenceName": "<File system linked service name>",
            "type": "LinkedServiceReference"
        },
        "schema": [ < physical schema, optional, auto retrieved during authoring > ],
        "typeProperties": {
            "location": {
                "type": "FileServerLocation",
                "folderPath": "root/folder/subfolder"
            },
            "columnDelimiter": ",",
            "quoteChar": "\"",
            "firstRowAsHeader": true,
            "compressionCodec": "gzip"
        }
    }
}

Copy activity properties

For a full list of sections and properties available for defining activities, see the Pipelines article. This section provides a list of properties supported by file system source and sink.

File system as source

Azure Data Factory supports the following file formats. Refer to each article for format-based settings.

• Avro format
• Binary format
• Delimited text format
• Excel format
• JSON format
• ORC format
• Parquet format
• XML format

The following properties are supported for file system under storeSettings settings in format-based copy source:

Property	Description	Required
type	The type property under storeSettings must be set to FileServerReadSettings.	Yes
Locate the files to copy:
OPTION 1: static path	Copy from the given folder/file path specified in the dataset. If you want to copy all files from a folder, additionally specify wildcardFileName as *.
OPTION 2: server side filter - fileFilter	File server side native filter, which provides better performance than OPTION 3 wildcard filter. Use * to match zero or more characters and ? to match zero or single character. Learn more about the syntax and notes from the Remarks under this section.	No
OPTION 3: client side filter - wildcardFolderPath	The folder path with wildcard characters to filter source folders. Such filter happens within the service, which enumerates the folders/files under the given path then apply the wildcard filter. Allowed wildcards are: * (matches zero or more characters) and ? (matches zero or single character); use ^ to escape if your actual folder name has wildcard or this escape char inside. See more examples in Folder and file filter examples.	No
OPTION 3: client side filter - wildcardFileName	The file name with wildcard characters under the given folderPath/wildcardFolderPath to filter source files. Such filter happens within the service, which enumerates the files under the given path then apply the wildcard filter. Allowed wildcards are: * (matches zero or more characters) and ? (matches zero or single character); use ^ to escape if your actual file name has wildcard or this escape char inside. See more examples in Folder and file filter examples.	Yes
OPTION 3: a list of files - fileListPath	Indicates to copy a given file set. Point to a text file that includes a list of files you want to copy, one file per line, which is the relative path to the path configured in the dataset. When using this option, don't specify file name in dataset. See more examples in File list examples.	No
Additional settings:
recursive	Indicates whether the data is read recursively from the subfolders or only from the specified folder. When recursive is set to true and the sink is a file-based store, an empty folder or subfolder isn't copied or created at the sink. Allowed values are true (default) and false. This property doesn't apply when you configure fileListPath.	No
deleteFilesAfterCompletion	Indicates whether the binary files are deleted from source store after successfully moving to the destination store. The file deletion is per file. This means that when the activity fails, you see some files already copied to the destination and deleted from source, while others still remain on source store. This property is only valid in binary files copy scenario. The default value: false.	No
modifiedDatetimeStart	Files filter based on the attribute: Last Modified. The files are selected if their last modified time is greater than or equal to modifiedDatetimeStart and less than modifiedDatetimeEnd. The time is applied to UTC time zone in the format of YYYY-MM-DDTHH:mm:ssZ. The properties can be NULL, which means no file attribute filter is applied to the dataset. When modifiedDatetimeStart has datetime value but modifiedDatetimeEnd is NULL, it means the files whose last modified attribute is greater than or equal with the datetime value are selected. When modifiedDatetimeEnd has datetime value but modifiedDatetimeStart is NULL, it means the files whose last modified attribute is less than the datetime value are selected. This property doesn't apply when you configure fileListPath.	No
modifiedDatetimeEnd	Same as modifiedDateTimeStart.	No
enablePartitionDiscovery	For files that are partitioned, specify whether to parse the partitions from the file path and add them as extra source columns. Allowed values are false (default) and true.	No
partitionRootPath	When partition discovery is enabled, specify the absolute root path in order to read partitioned folders as data columns. If it isn't specified, by default, - When you use file path in dataset or list of files on source, partition root path is the path configured in dataset. - When you use wildcard folder filter, partition root path is the subpath before the first wildcard. For example, assuming you configure the path in dataset as "root/folder/year=2020/month=08/day=27": - If you specify partition root path as "root/folder/year=2020", copy activity generates two more columns month and day with value "08" and "27" respectively, in addition to the columns inside the files. - If partition root path isn't specified, no extra column is generated.	No
maxConcurrentConnections	The upper limit of concurrent connections established to the data store during the activity run. Specify a value only when you want to limit concurrent connections.	No

Example:

"activities":[
    {
        "name": "CopyFromFileSystem",
        "type": "Copy",
        "inputs": [
            {
                "referenceName": "<Delimited text input dataset name>",
                "type": "DatasetReference"
            }
        ],
        "outputs": [
            {
                "referenceName": "<output dataset name>",
                "type": "DatasetReference"
            }
        ],
        "typeProperties": {
            "source": {
                "type": "DelimitedTextSource",
                "formatSettings":{
                    "type": "DelimitedTextReadSettings",
                    "skipLineCount": 10
                },
                "storeSettings":{
                    "type": "FileServerReadSettings",
                    "recursive": true,
                    "wildcardFolderPath": "myfolder*A",
                    "wildcardFileName": "*.csv"
                }
            },
            "sink": {
                "type": "<sink type>"
            }
        }
    }
]

File system as sink

Azure Data Factory supports the following file formats. Refer to each article for format-based settings.

• Avro format
• Binary format
• Delimited text format
• JSON format
• ORC format
• Parquet format

The following properties are supported for file system under storeSettings settings in format-based copy sink:

Property	Description	Required
type	The type property under storeSettings must be set to FileServerWriteSettings.	Yes
copyBehavior	Defines the copy behavior when the source is files from a file-based data store. Allowed values are: - PreserveHierarchy (default): Preserves the file hierarchy in the target folder. The relative path of source file to source folder is identical to the relative path of target file to target folder. - FlattenHierarchy: All files from the source folder are in the first level of the target folder. The target files have autogenerated names. - MergeFiles: Merges all files from the source folder to one file. If the file name is specified, the merged file name is the specified name. Otherwise, it's an autogenerated file name.	No
maxConcurrentConnections	The upper limit of concurrent connections established to the data store during the activity run. Specify a value only when you want to limit concurrent connections.	No

Example:

"activities":[
    {
        "name": "CopyToFileSystem",
        "type": "Copy",
        "inputs": [
            {
                "referenceName": "<input dataset name>",
                "type": "DatasetReference"
            }
        ],
        "outputs": [
            {
                "referenceName": "<Parquet output dataset name>",
                "type": "DatasetReference"
            }
        ],
        "typeProperties": {
            "source": {
                "type": "<source type>"
            },
            "sink": {
                "type": "ParquetSink",
                "storeSettings":{
                    "type": "FileServerWriteSettings",
                    "copyBehavior": "PreserveHierarchy"
                }
            }
        }
    }
]

Folder and file filter examples

This section describes the resulting behavior of the folder path and file name with wildcard filters.

folderPath	fileName	recursive	Source folder structure and filter result (files in bold are retrieved)
Folder*	(empty, use default)	false	FolderA     File1.csv     File2.json     Subfolder1         File3.csv         File4.json         File5.csv AnotherFolderB     File6.csv
Folder*	(empty, use default)	true	FolderA     File1.csv     File2.json     Subfolder1         File3.csv         File4.json         File5.csv AnotherFolderB     File6.csv
Folder*	*.csv	false	FolderA     File1.csv     File2.json     Subfolder1         File3.csv         File4.json         File5.csv AnotherFolderB     File6.csv
Folder*	*.csv	true	FolderA     File1.csv     File2.json     Subfolder1         File3.csv         File4.json         File5.csv AnotherFolderB     File6.csv

File list examples

This section describes the resulting behavior of using file list path in copy activity source.

Assuming you have the following source folder structure and want to copy the files in bold:

Sample source structure	Content in FileListToCopy.txt	Pipeline configuration
root     FolderA         File1.csv         File2.json         Subfolder1             File3.csv             File4.json             File5.csv     Metadata         FileListToCopy.txt	File1.csv Subfolder1/File3.csv Subfolder1/File5.csv	In dataset: - Folder path: root/FolderA In copy activity source: - File list path: root/Metadata/FileListToCopy.txt The file list path points to a text file in the same data store. It includes a list of files you want to copy. Each line contains the relative path to the file based on the root path configured in the dataset.

recursive and copyBehavior examples

This section describes the resulting behavior of the Copy operation for different combinations of recursive and copyBehavior values.

recursive	copyBehavior	Source folder structure	Resulting target
true	preserveHierarchy	Folder1     File1     File2     Subfolder1         File3         File4         File5	The target folder Folder1 is created with the same structure as the source: Folder1     File1     File2     Subfolder1         File3         File4         File5.
true	flattenHierarchy	Folder1     File1     File2     Subfolder1         File3         File4         File5	The target Folder1 is created with the following structure: Folder1     autogenerated name for File1     autogenerated name for File2     autogenerated name for File3     autogenerated name for File4     autogenerated name for File5
true	mergeFiles	Folder1     File1     File2     Subfolder1         File3         File4         File5	The target Folder1 is created with the following structure: Folder1     File1 + File2 + File3 + File4 + File 5 contents are merged into one file with autogenerated file name
false	preserveHierarchy	Folder1     File1     File2     Subfolder1         File3         File4         File5	The target folder Folder1 is created with the following structure Folder1     File1     File2 Subfolder1 with File3, File4, and File5 aren't picked up.
false	flattenHierarchy	Folder1     File1     File2     Subfolder1         File3         File4         File5	The target folder Folder1 is created with the following structure Folder1     autogenerated name for File1     autogenerated name for File2 Subfolder1 with File3, File4, and File5 are not picked up.
false	mergeFiles	Folder1     File1     File2     Subfolder1         File3         File4         File5	The target folder Folder1 is created with the following structure Folder1     File1 + File2 contents are merged into one file with autogenerated file name. autogenerated name for File1 Subfolder1 with File3, File4, and File5 aren't picked up.

Lookup activity properties

To learn details about the properties, check Lookup activity.

GetMetadata activity properties

To learn details about the properties, check GetMetadata activity.

Delete activity properties

To learn details about the properties, check Delete activity.

Legacy models

Legacy dataset model

Property	Description	Required
type	The type property of the dataset must be set to: FileShare	Yes
folderPath	Path to the folder. Wildcard filter is supported. Allowed wildcards are: * (matches zero or more characters) and ? (matches zero or single character); use ^ to escape if your actual folder name has wildcard or this escape char inside. Examples: rootfolder/subfolder/, see more examples in Sample linked service and dataset definitions and Folder and file filter examples.	No
fileName	Name or wildcard filter for the files under the specified "folderPath". If you don't specify a value for this property, the dataset points to all files in the folder. For filter, allowed wildcards are: * (matches zero or more characters) and ? (matches zero or single character). - Example 1: "fileName": "*.csv" - Example 2: "fileName": "???20180427.txt" Use ^ to escape if your actual file name has wildcard or this escape char inside. When fileName isn't specified for an output dataset and preserveHierarchy isn't specified in the activity sink, the copy activity automatically generates the file name with the following pattern: "Data.[activity run ID GUID].[GUID if FlattenHierarchy].[format if configured].[compression if configured]", for example "Data.0a405f8a-93ff-4c6f-b3be-f69616f1df7a.txt.gz"; if you copy from tabular source using table name instead of query, the name pattern is "[table name].[format].[compression if configured]", for example "MyTable.csv".	No
modifiedDatetimeStart	Files filter based on the attribute: Last Modified. The files are selected if their last modified time is greater than or equal to modifiedDatetimeStart and less than modifiedDatetimeEnd. The time is applied to UTC time zone in the format of YYYY-MM-DDTHH:mm:ssZ. Be aware the overall performance of data movement are impacted by enabling this setting when you want to do file filter from huge amounts of files. The properties can be NULL, which means no file attribute filter is applied to the dataset. When modifiedDatetimeStart has datetime value but modifiedDatetimeEnd is NULL, it means the files whose last modified attribute is greater than or equal with the datetime value are selected. When modifiedDatetimeEnd has datetime value but modifiedDatetimeStart is NULL, it means the files whose last modified attribute is less than the datetime value are selected.	No
modifiedDatetimeEnd	Files filter based on the attribute: Last Modified. The files are selected if their last modified time is greater than or equal to modifiedDatetimeStart and less than modifiedDatetimeEnd. The time is applied to UTC time zone in the format of "2018-12-01T05:00:00Z". Be aware the overall performance of data movement are impacted by enabling this setting when you want to do file filter from huge amounts of files. The properties can be NULL, which means no file attribute filter is applied to the dataset. When modifiedDatetimeStart has datetime value but modifiedDatetimeEnd is NULL, it means the files whose last modified attribute is greater than or equal with the datetime value are selected. When modifiedDatetimeEnd has datetime value but modifiedDatetimeStart is NULL, it means the files whose last modified attribute is less than the datetime value are selected.	No
format	If you want to copy files as-is between file-based stores (binary copy), skip the format section in both input and output dataset definitions. If you want to parse or generate files with a specific format, the following file format types are supported: TextFormat, JsonFormat, AvroFormat, OrcFormat, ParquetFormat. Set the type property under format to one of these values. For more information, see Text Format, Json Format, Avro Format, Orc Format, and Parquet Format sections.	No (only for binary copy scenario)
compression	Specify the type and level of compression for the data. For more information, see Supported file formats and compression codecs. Supported types are: GZip, Deflate, BZip2, and ZipDeflate. Supported levels are: Optimal and Fastest.	No

Example:

{
    "name": "FileSystemDataset",
    "properties": {
        "type": "FileShare",
        "linkedServiceName":{
            "referenceName": "<file system linked service name>",
            "type": "LinkedServiceReference"
        },
        "typeProperties": {
            "folderPath": "folder/subfolder/",
            "fileName": "*",
            "modifiedDatetimeStart": "2018-12-01T05:00:00Z",
            "modifiedDatetimeEnd": "2018-12-01T06:00:00Z",
            "format": {
                "type": "TextFormat",
                "columnDelimiter": ",",
                "rowDelimiter": "\n"
            },
            "compression": {
                "type": "GZip",
                "level": "Optimal"
            }
        }
    }
}

Legacy copy activity source model

Property	Description	Required
type	The type property of the copy activity source must be set to: FileSystemSource	Yes
recursive	Indicates whether the data is read recursively from the subfolders or only from the specified folder. Note when recursive is set to true and sink is file-based store, empty folder/sub-folder aren't be copied/created at sink. Allowed values are: true (default), false	No
maxConcurrentConnections	The upper limit of concurrent connections established to the data store during the activity run. Specify a value only when you want to limit concurrent connections.	No

Example:

"activities":[
    {
        "name": "CopyFromFileSystem",
        "type": "Copy",
        "inputs": [
            {
                "referenceName": "<file system input dataset name>",
                "type": "DatasetReference"
            }
        ],
        "outputs": [
            {
                "referenceName": "<output dataset name>",
                "type": "DatasetReference"
            }
        ],
        "typeProperties": {
            "source": {
                "type": "FileSystemSource",
                "recursive": true
            },
            "sink": {
                "type": "<sink type>"
            }
        }
    }
]

Legacy copy activity sink model

Property	Description	Required
type	The type property of the copy activity sink must be set to: FileSystemSink	Yes
copyBehavior	Defines the copy behavior when the source is files from file-based data store. Allowed values are: - PreserveHierarchy (default): preserves the file hierarchy in the target folder. The relative path of source file to source folder is identical to the relative path of target file to target folder. - FlattenHierarchy: all files from the source folder are in the first level of target folder. The target file names are autogenerated. - MergeFiles: merges all files from the source folder to one file. No record deduplication is performed during the merge. If the File Name is specified, the merged file name would be the specified name; otherwise, would be autogenerated file name.	No
maxConcurrentConnections	The upper limit of concurrent connections established to the data store during the activity run. Specify a value only when you want to limit concurrent connections.	No

Example:

"activities":[
    {
        "name": "CopyToFileSystem",
        "type": "Copy",
        "inputs": [
            {
                "referenceName": "<input dataset name>",
                "type": "DatasetReference"
            }
        ],
        "outputs": [
            {
                "referenceName": "<file system output dataset name>",
                "type": "DatasetReference"
            }
        ],
        "typeProperties": {
            "source": {
                "type": "<source type>"
            },
            "sink": {
                "type": "FileSystemSink",
                "copyBehavior": "PreserveHierarchy"
            }
        }
    }
]

Related content

For a list of data stores supported as sources and sinks by the copy activity, see supported data stores.