Azure Data Box Heavy limits
Consider these limits as you deploy and operate your Azure Data Box Heavy device. The following table describes these limits for the Data Box.
Data Box Heavy service limits
- If you use multiple storage accounts with the Data Box service, all the storage accounts should belong to the same Azure region.
- We recommend that you use no more than three storage accounts. Using more storage accounts could potentially affect the performance.
Data Box Heavy limits
- Data Box Heavy can store a maximum of 1 billion files per node.
- Data Box Heavy supports a maximum of 512 containers or shares per node in the cloud. The top-level directories within the user share become containers or Azure file shares in the cloud.
Azure Storage limits
This section describes the limits for Azure Storage service, and the required naming conventions for Azure Files, Azure block blobs, and Azure page blobs, as applicable to the Data Box service. Review the storage limits carefully and follow all the recommendations.
For the latest information on Azure storage service limits and best practices for naming shares, containers, and files, go to:
- Naming and referencing containers
- Naming and referencing shares
- Block blobs and page blob conventions
If there are any files or directories that exceed the Azure Storage service limits, or don't conform to Azure Files/Blob naming conventions, then these files or directories aren't ingested into the Azure Storage via the Data Box service.
Data upload caveats
- Containers, shares, and folders:
- Don't copy files directly to any of the precreated shares. You need to create a folder under the share and then copy files to that folder.
- A folder under the StorageAccount_BlockBlob and StorageAccount_PageBlob is a container. For instance, containers are created as StorageAccount_BlockBlob/container and StorageAccount_PageBlob/container.
- Each folder created directly under StorageAccount_AzFile is translated into an Azure File Share.
- Azure Blob Storage doesn't support directories. If you create a folder under the StorageAccount_BlockBlob folder, then virtual folders are created in the blob name. For Azure Files, the actual directory structure is maintained.
- Merging folder contents:
- Every file written into StorageAccount_BlockBlob and StorageAccount_PageBlob shares is uploaded as a block blob and page blob respectively.
- If a folder has the same name as an existing container, the folder's contents are merged with the container's contents. Files or blobs that aren't already in the cloud are added to the container. If a file or blob has the same name as a file or blob that's already in the container, the existing file or blob is overwritten.
- An upload to a blob in the Archive tier will fail if the container has an existing archived blob with the same name. While a blob is in the Archive tier, it can't be read or modified. If you need to overwrite a blob, make sure the blob isn't set to archive. For more information, see Archive access tier.
- Any empty directory hierarchy (without any files) created under StorageAccount_BlockBlob and StorageAccount_PageBlob folders isn't uploaded.
- If you use both the SMB and NFS protocols for data copies, we recommend that you:
- Use different storage accounts for SMB and NFS.
- Don't copy the same data to the same end destination in Azure using both SMB and NFS. In these cases, the final outcome can't be determined.
- Although copying via both SMB and NFS in parallel can work, we don't recommend doing that as it's prone to human error. Wait until your SMB data copy is complete before you start an NFS data copy.
- Upload management:
- To improve performance during data uploads, we recommend that you enable large file shares on the storage account and increase share capacity to 100 TiB. Large file shares are only supported for storage accounts with locally redundant storage (LRS).
- If there are any errors when uploading data to Azure, an error log is created in the target storage account. The path to this error log is available when the upload is complete, and you can review the log to take corrective action. Don't delete data from the source without verifying the uploaded data.
- File metadata and NTFS permissions can be preserved when the data is uploaded to Azure Files using guidance in Preserving file ACLs, attributes, and timestamps with Azure Data Box.
- The hierarchy of the files is maintained while uploading to the cloud for both blobs and Azure Files. For example, you copied a file at this path:
<container folder>\A\B\C.txt. This file is uploaded to the same path in cloud.
- If the CreateTime or LastWriteTime field for a file exceeds the allowable size during an upload, “Fri, 31 Dec 9999 23:59:59” replaces the original date in the Azure file property. The file upload succeeds, and no error is raised.
Azure storage account size limits
Here are the limits on the size of the data that's copied into a storage account. Make sure the data you upload conforms to these limits. For the most up-to-date information on these limits, see Scalability and performance targets for Blob storage and Azure Files scalability and performance targets.
|Size of data copied into Azure storage account||Default limit|
|Block blob and page blob||Maximum limit is the same as the Storage limit defined for Azure Subscription and it includes data from all the sources including Data Box.|
Azure object size limits
Here are the sizes of the Azure objects that can be written. Make sure that all the files that are uploaded conform to these limits.
|Azure object type||Default limit|
|Block blob||~ 4.75 TiB|
|Page blob||4 TiB
Every file uploaded in page blob format must be 512 bytes aligned (an integral multiple), else the upload fails.
VHD and VHDX are 512 bytes aligned.
|Azure Files||1 TiB|
|Managed disks||4 TiB
For more information on size and limits, see:
Azure block blob, page blob, and file naming conventions
|Container names for block blob and page blob||Must be a valid DNS name that is 3 to 63 characters long.
Must start with a letter or number.
Can contain only lowercase letters, numbers, and the hyphen (-).
Every hyphen (-) must be immediately preceded and followed by a letter or number.
Consecutive hyphens aren't permitted in names.
|Share names for Azure files||Same as above|
|Directory and file names for Azure files||
|Blob names for block blob and page blob|