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Performance FAQs for Azure NetApp Files

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This article answers frequently asked questions (FAQs) about Azure NetApp Files Performance.

What should I do to optimize or tune Azure NetApp Files performance?

You can take the following actions per the performance requirements:

  • Ensure the virtual machine (VM) is sized appropriately.
  • Enable Accelerated Networking for the VM.
  • Select the desired service level and size for the capacity pool.
  • Create a volume with the desired quota size for the capacity and performance.

There is no need to set accelerated networking for the network interface cards (NICs) in the dedicated subnet of Azure NetApp Files. Accelerated networking is a capability that only applies to Azure VMs. Azure NetApp Files NICs are optimized by design.

How do I monitor Azure NetApp Files volume performance

Azure NetApp Files volumes performance can be monitored through available metrics.

How do I convert throughput-based service levels of Azure NetApp Files to input/output operations per second (IOPS)?

You can convert megabytes per seconds (MBps) to IOPS with this formula:

IOPS = (MBps Throughput / KB per IO) * 1024

How do I change the service level of a volume?

You can change the service level of an existing volume by moving the volume to another capacity pool that uses the service level you want for the volume. See Dynamically change the service level of a volume.

How do I monitor Azure NetApp Files performance?

Azure NetApp Files provides volume performance metrics. You can also use Azure Monitor for monitoring usage metrics for Azure NetApp Files. See Metrics for Azure NetApp Files for the list of performance metrics for Azure NetApp Files.

Why is a workload's latency high when the IOPS are low?

In the absence of other symptoms (such as errors, network issues, or an application not responding), low IOP workloads are typically not a problem. Low IOPS are typically below 500-600 IOPS but can vary.

Azure NetApp Files responds to requests as they come in. A workload with few requests might appear to be higher, but is responding as expected. Low IOPS workloads (for example 5 IOPS and 32 KiB/s):

  • Aren't in the RAM cache, so need to go to disk more.
  • Don't have a high sample size, so are considered statistically irrelevant.
  • Don't have enough samples to average out any outliers.

Reported latency can reach the seconds or tens of seconds range due to the latency averaging skew. Increasing the workload on the volume with low IOPS can further help determine if latency skew is the reason the latency shows an inflated number.

What's the performance impact of Kerberos on NFSv4.1?

See Performance impact of Kerberos on NFSv4.1 volumes for information about security options for NFSv4.1, the performance vectors tested, and the expected performance impact.

What's the performance impact of using nconnect with Kerberos?

It is not recommended to use nconnect and sec=krb5* mount options together. Performance degradation has been observed when using the two options in combination.

The Generic Security Standard Application Programming Interface (GSS-API) provides a way for applications to protect data sent to peer applications. This data might be sent from a client on one machine to a server on another machine. 

When nconnect is used in Linux, the GSS security context is shared between all the nconnect connections to a particular server. TCP is a reliable transport that supports out-of-order packet delivery to deal with out-of-order packets in a GSS stream, using a sliding window of sequence numbers. When packets not in the sequence window are received, the security context is discarded, and a new security context is negotiated. All messages sent with in the now-discarded context are no longer valid, thus requiring the messages to be sent again. Larger number of packets in an nconnect setup cause frequent out-of-window packets, triggering the described behavior. No specific degradation percentages can be stated with this behavior.

Does Azure NetApp Files support SMB Direct?

No, Azure NetApp Files does not support SMB Direct.

Is NIC Teaming supported in Azure?

NIC Teaming isn't supported in Azure. Although multiple network interfaces are supported on Azure virtual machines, they represent a logical rather than a physical construct. As such, they provide no fault tolerance. Also, the bandwidth available to an Azure virtual machine is calculated for the machine itself and not any individual network interface.

Are jumbo frames supported?

Jumbo frames aren't supported with Azure virtual machines.

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