Prerequisites

Longhorn nodes must meet the following requirements:

• AMD64 or ARM64 CPU

  NOTICE

  AMD64 CPUs require SSE4.2 instruction support.

• Linux kernel

  5.19 or later is required for NVMe over TCP support

  NOTICE

  Host machines with Linux kernel 5.15 may unexpectedly reboot when volume-related IO errors occur. Update the Linux kernel on Longhorn nodes to version 5.19 or later to prevent such issues.

  v6.7 or later is recommended for improved system stability

  NOTICE

  Memory corruption may occur on hosts using versions of the Linux kernel earlier than 6.7, as highlighted by this SPDK upstream issue: https://github.com/spdk/spdk/issues/3116#issuecomment-1890984674. In Longhorn environment the kernel panic can be caused by prevalent IO timeouts in communications between the nvme-tcp driver and SPDK. Update the Linux kernel on Longhorn nodes to version 6.7 or later to prevent the issue from occurring.

• Linux kernel modules

  • uio
  • uio_pci_generic
  • nvme-tcp

• Huge page support

  • 2 GiB of 2 MiB-sized pages

Notice

CPU

When the V2 Data Engine is enabled, each instance-manager pod utilizes 1 CPU core. This high CPU usage is attributed to the spdk_tgt process running within each instance-manager pod. The spdk_tgt process is responsible for handling input/output (IO) operations and requires intensive polling. As a result, it consumes 100% of a dedicated CPU core to efficiently manage and process the IO requests, ensuring optimal performance and responsiveness for storage operations.

Memory

SPDK leverages huge pages for enhancing performance and minimizing memory overhead. You must configure 2 MiB-sized huge pages on each Longhorn node to enable usage of huge pages. Specifically, 1024 pages (equivalent to a total of 2 GiB) must be available on each Longhorn node.

Disk

SPDK leverages kernel drivers to support every kind of disk that Linux supports. However, SPDK is equipped with a user space NVMe driver that provides zero-copy, highly parallel, direct access to an SSD from a user space application. Because of this, using local NVMe disks is highly recommended for enabling V2 volumes to achieve optimal storage performance.