Append Blob is a new Microsoft Azure Storage blob type which is optimized for fast append operations, making it ideal for scenarios where the data must be added to an existing blob without modifying the existing contents of that blob (E.g. logging, auditing). For more details, please go to Introducing Azure Storage Append Blob.
Both AzCopy 3.2.0 and 4.2.0-preview will include the support for Append Blob in the following scenarios:
- Download Append Blob, same as downloading a block or page blob
- Upload Append Blob, add option /BlobType:Append to specify the blob type
- Copy Append Blob, there is no need to specify the /BlobType
Note that when uploading or copying append blobs with names that already exist in the destination, AzCopy will prompt either “overwrite or skip” message. Trying to overwrite a blob with the same name but a mismatched blob type will fail. For example, AzCopy will report a failure when overwriting a Block Blob with an Append Blob.
AzCopy does not include the support for appending data to an existing append blob, and if you are using an older version AzCopy, the download and copy operations will fail with the following error message when the source container includes Append Blob.
Error parsing the source location “[the source URL specified in the command line]”: The remote server returned an error: (409) Conflict. The type of a blob in the container is unrecognized by this version.
File Storage Asynchronous Copy (4.2.0 only)
Azure Storage File Service adds several new features with Storage Service REST version 2015-2-21, please find more details at Azure Storage File Preview Update.
In the previous version of AzCopy 4.1.0, we introduced synchronous copy for Blob and File, now AzCopy 4.2.0-preview includes the support for the following File Storageasynchronous copy scenarios.
Unlike synchronous copy which simulate the copy by downloading the blobs from the source storage endpoint to local memory and then uploading them to the destination storage end point, the File Storage asynchronous copy is a server side copy which is running in the background and you can get the copy status programmatically, please find more details at Server Side Copy File.
- Asynchronous copying from File Storage to File Storage
- Asynchronous copying from File Storage to Block Blob
- Asynchronous copying from Block/Page Blob Storage to File Storage
Note that asynchronous copying from File Storage to Page Blob is not supported.
File Storage Share SAS (Preview version 4.2.0 only)
Besides the File asynchronous copy, another File Storage new feature ‘File Share SAS’ will be supported in AzCopy 4.2.0-preview as well.
Now you can use option /SourceSAS and /DestSAS to authenticate the file transfer request.
For more details about File Storage share SAS, please visit Azure Storage File Preview Update.
Export Table Storage entities to CSV (Preview version 4.2.0 only)
AzCopy allows end users to export Table entities to local files in JSON format since the 4.0.0 preview version, now you can specify the new option /PayloadFormat:<JSON | CSV> to export data to CSV files. Without specifying this new option, AzCopy will export Table entities to JSON files.
Besides the data files with .csv extension that will be found in the place specified by the parameter /Dest, AzCopy will generate scheme file with file extension .schema.csv for each data file.
Note that AzCopy does not include the support for “importing” CSV data file, you can use JSON format to export/import as you did in previous version of AzCopy.
Specify the manifest file name when exporting Table entities (Preview version 4.2.0 only)
AzCopy requires end users to specify the option /Manifest when importing table entities, in previous version the manifest file name is decided by AzCopy during the exporting which looks like “myaccount_mytable_timestamp.manifest”, and users need to find the name in the destination folder firstly before writing the import command line.
Now you can specify the manifest file name during the exporting by option /Manifest which should bring more flexibility and convenience to your importing scenarios.
Enable FIPS compliant MD5 algorithm
AzCopy by default uses .NET MD5 implementation to calculate the MD5 when copying objects, now we include the support for FIPS compliant MD5 setting to fulfill some scenarios’ security requirements.
You can create an app.config file “AzCopy.exe.config” with property “AzureStorageUseV1MD5” and put it aside with AzCopy.exe.
For property “AzureStorageUseV1MD5”
- true – The default value, AzCopy will use .NET MD5 implementation.
- false – AzCopy will use FIPS compliant MD5 algorithm.
Note that FIPS compliant algorithms is disabled by default on your Windows machine, you can type secpol.msc in your Run window and check this switch at “Security Setting->Local Policy->Security Options->System cryptography: Use FIPS compliant algorithms for encryption, hashing and signing”.
As always, we look forward to your feedback.
Microsoft Azure Storage Team