Instance volume limits - Amazon Elastic Compute Cloud
Volume limits for instances built on the Nitro SystemVolume limits for Xen-based instances
Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Instance volume limits

The maximum number of Amazon EBS volumes that you can attach to an instance depends on the instance type and instance size. When considering how many volumes to attach to your instance, you should consider whether you need increased I/O bandwidth or increased storage capacity.

Bandwidth versus capacity

For consistent and predictable bandwidth use cases, use Amazon EBS–optimized instances with General Purpose SSD volumes or Provisioned IOPS SSD volumes. For maximum performance, match the IOPS you have provisioned for your volumes with the bandwidth available for your instance type.

For RAID configurations, you might find that arrays larger than 8 volumes have diminished performance returns due to increased I/O overhead. Test your individual application performance and tune it as required.

Volume limits for instances built on the Nitro System

Dedicated Amazon EBS volume limit

The following Nitro instance types have a dedicated Amazon EBS volume limit of up to 128 attachments, depending on instance size. The limit is not shared with other device attachments. In other words, you can attach any number of Amazon EBS volumes up to the volume attachment limit, regardless of the number of attached devices, such as NVMe instance store volumes and network interfaces.

  • General purpose: M7i, M7a

  • Compute optimized: C7i

  • Memory optimized: R7a, R7iz

The volume limits depend on the instance size. The following table shows the limit for each instance size.

Instance size Volume limit
medium | large | xlarge | 2xlarge | 4xlarge | 8xlarge | 12xlarge 32
16xlarge 48
24xlarge 64
32xlarge 88
48xlarge 128
metal-48xl 79
Shared Amazon EBS volume limit

All other Nitro instance types have a volume attachment limit that is shared between Amazon EBS volumes, network interfaces, and NVMe instance store volumes. You can attach any number of Amazon EBS volumes up to that limit, less the number of attached network interfaces and NVMe instance store volumes. Keep in mind that every instance must have at least one network interface, and that NVMe instance store volumes are automatically attached at launch.

Most of these instances support a maximum of 28 attachments. For example, if you have no additional network interface attachments on an m5.xlarge instance, you can attach up to 27 EBS volumes (28 volume limit - 1 network interface). If you have two additional network interfaces on an m5.xlarge instance, you can attach up to 25 EBS volumes (28 volume limit - 3 network interfaces). Similarly, if you have two additional network interfaces on an m5d.xlarge instance, which has 1 NVMe instance store volume, you can attach up to 24 EBS volumes (28 volume limit - 3 network interfaces - 1 NVMe instance store volume).

The following exceptions apply:

  • Most bare metal instances support a maximum of 31 EBS volumes.

  • High memory virtualized instances support a maximum of 27 EBS volumes.

  • High memory bare metal instances support a maximum of 19 EBS volumes.

  • mac1.metal instances support a maximum of 16 EBS volumes.

  • inf1.24xlarge instances support a maximum of 11 EBS volumes.

  • g5.48xlarge instances support a maximum of 9 EBS volumes.

  • d3.8xlarge and d3en.12xlarge instances support a maximum of 3 EBS volumes.

  • For accelerated computing instances, the attached accelerators count towards the shared volume limit. For example, for p4d.24xlarge instances, which have a shared volume limit of 28, 8 GPUs, and 8 NVMe instance store volumes, you can attach up to 11 Amazon EBS volumes (28 volume limit - 1 network interface - 8 GPUs - 8 NVMe instance store volumes).

Volume limits for Xen-based instances

The following table shows the volume limits for Xen-based Windows instances based on the driver used. That these numbers include the root volume, plus any attached instance store volumes and Amazon EBS volumes.

Important

Attaching more than the following number of volumes to a Xen-based Windows instance is supported on a best effort basis only and is not guaranteed.

Driver Volume Limit

Amazon PV

26

Citrix PV

26

Red Hat PV

17

We recommend that you do not that attach more than 26 volumes to a Xen-based Windows instance with Amazon PV or Citrix PV drivers, as it is likely to cause performance issues.

To determine which PV drivers your instance is using, or to upgrade your Windows instance from Red Hat to Citrix PV drivers, see Upgrade PV drivers on Windows instances.

For more information about how device names are related to volumes, see Map disks to volumes on your Windows instance.