Amazon EBS and NVMe
With the following instances, EBS volumes are exposed as NVMe block devices: C5, C5d,
i3.metal, M5, M5d, R5, R5d, T3, u-6tb1.metal, u-9tb1.metal, u-12tb1.metal, and z1d.
The device names are /dev/nvme0n1, /dev/nvme1n1,
and so on. The device names that you specify in a block device mapping are renamed
using NVMe
device names (/dev/nvme[0-26]n1).
Note
The EBS performance guarantees stated in Amazon EBS Product Details are valid regardless of the block-device interface.
Some of these instance types also support NVMe instance store volumes. For more information, see NVMe SSD Volumes.
Identifying the EBS Device
Amazon Linux AMIs
With Amazon Linux AMI 2017.09.01 or later (including Amazon Linux 2), you can run the ebsnvme-id command as follows to map the NVMe device name to a volume ID and device name.
[ec2-user ~]$sudo /sbin/ebsnvme-id /dev/nvme1n1Volume ID: vol-01324f611e2463981 /dev/sdf
Amazon Linux also creates a symbolic link from the device name in the block device
mapping (for example, /dev/sdf), to the NVMe device name.
Other Linux AMIs
With a kernel version of 4.2 or later, you can run the nvme
id-ctrl command as follows to map an NVMe device to a volume ID.
First, install the NVMe command line package, nvme-cli,
using the package management tools for your Linux distribution.
The following example gets the volume ID and device name. The device name is available through the NVMe controller vendor specific extension (bytes 384:4095 of the controller identification).
[ec2-user ~]$sudo nvme id-ctrl -v /dev/nvme1n1NVME Identify Controller: vid : 0x1d0f ssvid : 0x1d0f sn :vol01234567890abcdefmn : Amazon Elastic Block Store ... 0000: 2f 64 65 76 2f 73 64 6a 20 20 20 20 20 20 20 20 "/dev/sdf..."
The lsblk command lists available devices and their
mount points (if applicable). This helps you determine the correct device name to
use.
In this example, /dev/nvme0n1p1 is mounted as the root device and
/dev/nvme1n1 is attached but not mounted.
[ec2-user ~]$lsblkNAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT nvme1n1 259:3 0 100G 0 disk nvme0n1 259:0 0 8G 0 disk nvme0n1p1 259:1 0 8G 0 part / nvme0n1p128 259:2 0 1M 0 part
Working with NVMe EBS Volumes
If you are using Linux kernel 4.2 or later, any change you make to the volume size of an NVMe EBS volume is automatically reflected in the instance. For older Linux kernels, you might need to detach and attach the EBS volume or reboot the instance for the size change to be reflected. With Linux kernel 3.19 or later, you can use the hdparm command as follows to force a rescan of the NVMe device:
[ec2-user ~]$sudo hdparm -z /dev/nvme1n1
Before you detach an NVMe EBS volume, you should sync and unmount it. When you detach an NVMe EBS volume, the force option is implicitly enabled. Therefore, the instance does not have an opportunity to flush file system caches or metadata before detaching the volume.
I/O Operation Timeout
NVMe EBS volumes use the default NVMe driver provided by the operating
system. Most operating systems specify a timeout for I/O operations submitted to NVMe
devices. The default timeout is 30 seconds and can be changed using the
nvme_core.io_timeout boot parameter (or the
nvme.io_timeout boot parameter for Linux kernels prior to version 4.6).
For an experience similar to EBS volumes attached to Xen instances, we recommend setting
this to the highest value possible. For current kernels, the maximum is 4294967295,
while for earlier kernels the maximum is 255. If you are using the most recent version
of the Amazon Linux AMI, the timeout is set to 4294967295 by default. For other operating
systems, check with the AMI provider about the default timeout value.
