Azure File Sync Question

Question

Please confirm how often Azure File Sync will sync my files when I'm writing to Azure Files. I understand that the sync frequency is every 24 hours when I am pulling data down from Azure Files. Thank you!

Answer 1

@Mary Quinn Welcome to Microsoft Q&A Forum, Thank you for posting your query here!

If I created a file directly in my Azure file share over SMB or through the portal, how long does it take for the file to sync to servers in the sync group?

Changes made to the Azure file share by using the Azure portal or SMB are not immediately detected and replicated like changes to the server endpoint. Azure Files does not yet have change notifications or journaling, so there's no way to automatically initiate a sync session when files are changed. On Windows Server, Azure File Sync uses Windows USN journaling to automatically initiate a sync session when files change.

To detect changes to the Azure file share, Azure File Sync has a scheduled job called a change detection job. A change detection job enumerates every file in the file share, and then compares it to the sync version for that file. When the change detection job determines that files have changed, Azure File Sync initiates a sync session. The change detection job is initiated every 24 hours. Because the change detection job works by enumerating every file in the Azure file share, change detection takes longer in larger namespaces than in smaller namespaces**. For large namespaces, it might take longer than once every 24 hours to determine which files have changed.

**To immediately sync files that are changed in the Azure file share, the Invoke-AzStorageSyncChangeDetection PowerShell cmdlet can be used to manually initiate the detection of changes in the Azure file share. This cmdlet is intended for scenarios where some type of automated process is making changes in the Azure file share or the changes are done by an administrator (like moving files and directories into the share).**** For end user changes, the recommendation is to install the Azure File Sync agent in an IaaS VM and have end users access the file share through the IaaS VM. This way all changes will quickly sync to other agents without the need to use the Invoke-AzStorageSyncChangeDetection cmdlet. To learn more, see the Invoke-AzStorageSyncChangeDetection

How long does it take for Azure File Sync to upload 1TiB of data?

Performance will vary based on your environmental settings, configuration, and whether this is an initial sync or an ongoing sync. For more information, see Azure File Sync performance metrics

If the same file is changed on two servers at approximately the same time, what happens?
Azure File Sync uses a simple conflict-resolution strategy: we keep both changes to files that are changed in two endpoints at the same time. The most recently written change keeps the original file name. The older file (determined by LastWriteTime) has the endpoint name and the conflict number appended to the filename. For server endpoints, the endpoint name is the name of the server. For cloud endpoints, the endpoint name is Cloud. The name follows this taxonomy:

<FileNameWithoutExtension>-<endpointName>[-#].<ext>

For example, the first conflict of CompanyReport.docx would become CompanyReport-CentralServer.docx if CentralServer is where the older write occurred. The second conflict would be named CompanyReport-CentralServer-1.docx. Azure File Sync supports 100 conflict files per file. Once the maximum number of conflict files has been reached, the file will fail to sync until the number of conflict files is less than 100.

Hope this helps!
Kindly let us know if the above helps or you need further assistance on this issue.

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