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Troubleshoot Azure Files

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This article lists common issues related to Azure Files. It also provides possible causes and resolutions for these issues.

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Applies to

File share type SMB NFS
Standard file shares (GPv2), LRS/ZRS
Standard file shares (GPv2), GRS/GZRS
Premium file shares (FileStorage), LRS/ZRS

General troubleshooting first steps

If you encounter problems with Azure Files, start with the following steps.

Check DNS resolution and connectivity to your Azure file share

The most common problem encountered by Azure Files customers is that mounting or accessing the Azure file share fails because of an incorrect networking configuration. This can happen with any of the three file sharing protocols that Azure Files supports: SMB, NFS, and FileREST.

The following table provides the SMB, NFS, and FileREST requirements for which of the network endpoints of a storage account they can use, and which port that endpoint can be accessed over. To learn more about network endpoints, see Azure Files networking considerations.

Protocol name Unrestricted public endpoint Restricted public endpoint Private endpoint Required port
SMB TCP 445
NFS TCP 2049
FileREST TCP 443 (HTTPS), TCP 80 (HTTP)

To mount or access a file share successfully, your client must:

  • Be able to resolve the fully qualified domain name of the storage account (ex. mystorageaccount.file.core.windows.net) to the correct IP address for the desired network endpoint of the storage account.

  • Establish a successful TCP connection to the correctly resolved IP address on the correct port for the desired protocol.

Note

You must use the fully qualified domain name (FQDN) for your storage account when mounting/accessing the share. The following commands will let you see the current IP addresses of the network endpoints of your storage account, but you should not hardcode these IP addresses into any scripts, firewall configurations, or other locations. IP addresses aren't guaranteed to remain the same, and may change at any time.

Check DNS name resolution

The following command lets you test the DNS name resolution of your storage account.

# If you have changed the DNS configuration in your environment, it may be helpful to clear
# the DNS client cache to ensure you're getting the updated DNS name resolution.
Clear-DnsClientCache

# Replace this value with the fully qualified domain name for your storage account. 
# Different storage accounts, especially in different Azure environments, 
# may have different suffixes than file.core.windows.net, so be sure to use the correct
# suffix for your storage account.
$hostName = "mystorageaccount.file.core.windows.net"

# Do the name resolution. Piping to Format-List is optional.
Resolve-DnsName -Name $hostName | Format-List

The output returned by Resolve-DnsName may be different depending on your environment and desired networking configuration. For example, if you're trying to access a public endpoint of a storage account that doesn't have any private endpoints configured, you will see the following output. In this output, x.x.x.x is the IP address of the cluster file.phx10prdstf01a.store.core.windows.net of the Azure storage platform that serves your storage account.

Name       : mystorageaccount.file.core.windows.net
Type       : CNAME
TTL        : 27
Section    : Answer
NameHost   : file.phx10prdstf01a.store.core.windows.net

Name       : file.phx10prdstf01a.store.core.windows.net
QueryType  : A
TTL        : 60
Section    : Answer
IP4Address : x.x.x.x

If you're trying to access the public endpoint of a storage account that has one or more private endpoints configured, you will see the following output. The output includes an extra CNAME record for mystorageaccount.privatelink.file.core.windows.net, positioned between the usual FQDN of the storage account and the name of the storage cluster. This enables name resolution to the public endpoint's IP address when the user is accessing from the internet, and resolution to the private endpoint's IP address when the user is accessing from inside of an Azure virtual network (or peered network).

Name       : mystorageaccount.file.core.windows.net
Type       : CNAME
TTL        : 60
Section    : Answer
NameHost   : mystorageaccount.privatelink.file.core.windows.net

Name       : mystorageaccount.privatelink.file.core.windows.net
Type       : CNAME
TTL        : 60
Section    : Answer
NameHost   : file.phx10prdstf01a.store.core.windows.net


Name       : file.phx10prdstf01a.store.core.windows.net
QueryType  : A
TTL        : 60
Section    : Answer
IP4Address : x.x.x.x

If you are resolving to a private endpoint, you would normally expect an A record for mystorageaccount.privatelink.file.core.windows.net that maps to your private endpoint's IP address:

Name                   : mystorageaccount.file.core.windows.net
Type                   : CNAME
TTL                    : 53
Section                : Answer
NameHost               : mystorageaccount.privatelink.file.core.windows.net


Name                   : mystorageaccount.privatelink.file.core.windows.net
QueryType              : A
TTL                    : 10
Section                : Answer
IP4Address             : 10.0.0.5

Check TCP connectivity

The following command lets you test your client's ability to make a TCP connection to the resolved IP address/port number.

# Replace this value with the fully qualified domain name for your storage account. 
# Different storage accounts, especially in different Azure environments, 
# may have different suffixes than file.core.windows.net, so be sure to use the correct
# suffix for your storage account.
$hostName = "mystorageaccount.file.core.windows.net"

# Do the TCP connection test - see the above protocol/port table to figure out which
# port to use for your test. This test uses port 445, the port used by SMB.
Test-NetConnection -ComputerName $hostName -Port 445

If the connection was successfully established, you should expect to see the following result:

ComputerName     : mystorageAccount.file.core.windows.net
RemoteAddress    : x.x.x.x
RemotePort       : 445
InterfaceAlias   : Ethernet
SourceAddress    : y.y.y.y
TcpTestSucceeded : True

Run diagnostics

Both Windows clients and Linux clients can use AzFileDiagnostics to ensure that the client environment has the correct prerequisites. AzFileDiagnostics automates symptom detection and helps set up your environment to get optimal performance.

Common troubleshooting areas

For more detailed information, choose the subject area you'd like to troubleshoot.

Some issues can be related to more than one subject area (both connectivity and performance, for example).

Need help?

If you still need help, contact support to get your problem resolved quickly.

See also

Contact us for help

If you have questions or need help, create a support request, or ask Azure community support. You can also submit product feedback to Azure feedback community.