NVM Express (NVMe) devices are flash memory chips connected to a system via the PCI-E bus. They are among the fastest memory chips available on the market, faster than Solid State Drives (SSD) connected over the SATA bus.
NVM Express block device (CONFIG_BLK_DEV_NVME) must be activated to gain NVMe device support:
Device Drivers ---> <*> NVM Express block device
Devices will show up under /dev/nvme*.
Partition tables and formatting can be performed the same as any other block device.
Identifying the device
There are minor differences in the naming scheme for devices and partitions when compared to SATA devices.
NVMe partitions generally show a p before the partition number. NVMe devices also include namespace support, using a n before listing the namespace. Therefore the first device in the first namespace with one partition will be at the following location: /dev/nvme0n1p1. The device name is nvme0, in namespace 1, and partition 1.
Hdparm can be used to get the raw read/write speed of a NVMe device. Passing the
-t option instructs hdparm to perform timings of device reads,
-T performs timings of cache reads, and
--direct bypasses the page cache and causes reads to go directly from the drive into hdparm's buffers in raw mode:
hdparm -tT --direct /dev/nvme0n1
Performance and maintenance
Since NVMe devices share the flash memory technology basis with common SSDs, the same performance and longevity considerations apply. For details consult the SSD article.
- SSD — provides guidelines for basic maintenance, such as enabling discard/trim support, for SSDs (Solid State Drives) on Linux.
- https://medium.com/@metebalci/a-quick-tour-of-nvm-express-nvme-3da2246ce4ef - An excellent article describing the differences in recent disk drive technology, but focusing on NVMe.