Document Details
Smb Performance
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This page contains Windows bias
About This Page
This page is part of the Azure documentation. It contains code examples and configuration instructions for working with Azure services.
Bias Analysis
Bias Types:
⚠️
powershell_heavy
⚠️
windows_first
⚠️
windows_tools
⚠️
missing_linux_example
Summary:
The documentation page demonstrates a strong Windows bias. All configuration and verification steps for SMB Multichannel are exclusively described for Windows clients, using Windows PowerShell commands and Windows-specific tools (e.g., robocopy, diskspd.exe). There are no Linux examples or instructions for enabling, verifying, or testing SMB Multichannel from Linux clients. References to documentation and tools are Windows-centric, and Linux support is only mentioned in passing (for metadata caching), without any actionable guidance.
Recommendations:
- Add explicit guidance and examples for configuring, enabling, and verifying SMB Multichannel on Linux clients (e.g., using modern Linux kernels with SMB3.1.1, mounting with appropriate cifs options, and using smbstatus or similar tools).
- Provide Linux command-line equivalents for all PowerShell/Windows commands (e.g., show how to check SMB Multichannel status on Linux).
- Include Linux-compatible performance testing tools (e.g., fio, dd, or iozone) alongside Windows tools like diskspd.exe and robocopy.
- Reference Linux documentation for SMB Multichannel (e.g., Samba, kernel.org) in the 'Next steps' and throughout the article.
- Ensure that all feature descriptions and limitations clarify support for both Windows and Linux clients, and provide parity in troubleshooting and verification steps.
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| 2025-09-10 00:00 | #107 | completed | ✅ Clean |
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| 2025-07-24 00:00 | #59 | completed | ✅ Clean |
| 2025-07-23 00:00 | #58 | completed | ✅ Clean |
| 2025-07-13 21:37 | #48 | completed | ❌ Biased |
| 2025-07-12 23:44 | #41 | in_progress | ❌ Biased |
Flagged Code Snippets
Get-SmbClientConfiguration | Select-Object -Property EnableMultichannel
---
> [!IMPORTANT]
> - Although listed under Preview Features, we honor GA SLAs and will soon make this the default for all accounts, removing the need for registration.
> - Allow 2-6 hours for accounts to be onboarded once registration is complete.
### Performance improvements with metadata caching
Most workloads or usage patterns that contain metadata can benefit from metadata caching. To determine if your workload contains metadata, you can [use Azure Monitor](analyze-files-metrics.md#monitor-utilization) to split the transactions by API dimension.
Typical metadata-heavy workloads and usage patterns include:
- Web/app services
- DevOps tasks
- Indexing/batch jobs
- Virtual desktops with home directories or other workloads that are primarily interacting with many small files, directories, or handles
The following diagrams depict potential results.
#### Reduce metadata latency
By caching file and directory paths for future lookups, metadata caching can reduce latency on frequently accessed files and directories by 30% or more for metadata-heavy workloads at scale.
:::image type="content" source="media/smb-performance/metadata-caching-latency.jpg" alt-text="Chart showing latency in milliseconds with and without metadata caching." border="false":::
#### Increase available IOPS
Metadata caching can increase available IOPS by more than 60% for metadata-heavy workloads at scale.
:::image type="content" source="media/smb-performance/metadata-caching-iops.jpg" alt-text="Chart showing available IOPS with and without metadata caching." border="false":::
#### Increase network throughput
Metadata caching can increase network throughput by more than 60% for metadata-heavy workloads at scale.
:::image type="content" source="media/smb-performance/metadata-caching-throughput.jpg" alt-text="Chart showing network throughput with and without metadata caching." border="false":::
## Register for increased file handle limits (preview)
To increase the maximum number of concurrent handles per file and directory for SSD SMB file shares from 2,000 to 10,000, register for the preview feature using the Azure portal or Azure PowerShell. If you have questions, email azfilespreview@microsoft.com.
# [Azure portal](#tab/portal)
1. Sign in to the [Azure portal](https://portal.azure.com?azure-portal=true).
2. Search for and select **Preview features**.
3. Select the **Type** filter and select **Microsoft.Storage**.
4. Select **Azure Premium Files Increased Maximum Opened Handles Count** and then select **Register**.
# [Azure PowerShell](#tab/powershell)
To register your subscription using Azure PowerShell, run the following commands. Replace `<your-subscription-id>` and `<your-tenant-id>` with your own values.