Understand maxfiles limits in Azure NetApp Files

Azure NetApp Files volumes have a value called maxfiles that refers to the maximum number of files and folders (also known as inodes) a volume can contain. When the maxfiles limit is reached, clients receive "out of space" messages when attempting to create new files or folders. If you experience this issue, contact Microsoft technical support.

The maxfiles limit for an Azure NetApp Files volume is based on the size (quota) of the volume, where the service dynamically adjusts the maxfiles limit for a volume based on its provisioned size and uses the following guidelines.

  • For regular volumes less than or equal to 683 GiB, the default maxfiles limit is 21,251,126.
  • For regular volumes greater than 683 GiB, the default maxfiles limit is approximately one file (or inode) per 32 KiB of allocated volume capacity up to a maximum of 2,147,483,632.
  • For large volumes, the default maxfiles limit is approximately one file (or inode) per 32 KiB of allocated volume capacity up to a default maximum of 15,938,355,048.
  • Each inode uses roughly 288 bytes of capacity in the volume. Having many inodes in a volume can consume a non-trivial amount of physical space overhead on top of the capacity of the actual data.
    • If a file is less than 64 bytes in size, it's stored in the inode itself and doesn't use additional capacity. This capacity is only used when files are actually allocated to the volume.
    • Files larger than 64 bytes do consume additional capacity on the volume. For instance, if there are one million files greater than 64 bytes in an Azure NetApp Files volume, then approximately 274 MiB of capacity would belong to the inodes.

The following table shows examples of the relationship maxfiles values based on volume sizes for regular volumes.

Volume size Estimated maxfiles limit
0 – 683 GiB 21,251,126
1 TiB (1,073,741,824 KiB) 31,876,709
10 TiB (10,737,418,240 KiB) 318,767,099
50 TiB (53,687,091,200 KiB) 1,593,835,519
100 TiB (107,374,182,400 KiB) 2,147,483,632

The following table shows examples of the relationship maxfiles values based on volume sizes for large volumes.

Volume size Estimated maxfiles limit
50 TiB (53,687,091,200 KiB) 1,593,835,512
100 TiB (107,374,182,400 KiB) 3,187,671,024
200 TiB (214,748,364,800 KiB) 6,375,342,024
500 TiB (536,870,912,000 KiB) 15,938,355,048

To see the maxfiles allocation for a specific volume size, check the Maximum number of files field in the volume’s overview pane.

Screenshot of volume overview menu.

You can't set maxfiles limits for data protection volumes via a quota request. Azure NetApp Files automatically increases the maxfiles limit of a data protection volume to accommodate the number of files replicated to the volume. When a failover happens on a data protection volume, the maxfiles limit remains the last value before the failover. In this situation, you can submit a maxfiles quota request for the volume.

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