How to check the disk access speed for a VM instance

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Updated at December 17, 2025

Case description

You need to find out the disk access speed of a virtual machine and what it depends on.

The speed depends on the disk type, the physical block size, and the disk size. To learn more, see this article.

Note

The access speed is not affected by whether the disk is a boot or data one.

Disks have limits on IOPS and bandwidth. You can read more about this here.

For maximum IOPS, limit the size of reads and writes to 4 KB or less, and for maximum bandwidth, to 4 MB.