Does "/usr/bin/raw" command available in Red Hat Enterprise Linux 9?

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux 9
    • kernel-5.14.0-70.22.1.el9_0.x86_64 and later
  • util-linux-2.37.4-3.el9.x86_64 and later

Issue

  • Which package provides the /usr/bin/raw command on RHEL 9?
  • Can't find /usr/bin/raw command on RHEL9?
  • "Process Request task (pid ) is using the deprecated raw device" messages in RHEL 8.

Resolution

  • Applications should use open() calls with the O_DIRECT option instead of depending on and utilizing the /dev/raw character devices.

    • /dev/raw devices are a character device that maps on top of a block storage device (disk) and converts all reads and writes into direct io accesses. Opening the device or files on a device in the O_DIRECT mode accomplish the same functionality.

  • The /usr/bin/raw command interface for /dev/raw devices was removed from the util-linux shipped in RHEL 9.

    • The /dev/raw driver was removed from the upstream kernel as of v5.14.
    • The /dev/raw interface was removed upstream and so is no longer available within the RHEL 9 kernel which is based on the v5.14 upstream kernel.

Root Cause

  • /dev/raw support was removed from RHEL 9 per upstream changes

  • /dev/raw kernel driver support was removed upstream via the following kernel commit:

    commit 603e4922f1c81fc2ed3a87b4f91a8d3aafc7e093
Date:   Mon May 31 10:25:26 2021 +0300

remove the raw driver

The raw driver used to provide direct unbuffered access to block devices
before O_DIRECT was invented.  It has been obsolete for more than a
decade.

  • /usr/bin/raw utility was removed from RHEL 9's util-linux package as noted here within that package's change log:

    * Fri Jul 23 2021 - 2.37.1-1
- upgrade to v2.37.1 (fix #1984900, #1971989, and #1938894)
- fix #1984771 - disable raw

  • Within RHEL 8's man raw documentation there is an added note hinting on the deprecation of the /dev/raw interface within the kernel and likely removal in a later major kernel release:

    NOTE
    Rather than using raw devices applications should prefer open(2) devices, such 
    as /dev/sda1, with the O_DIRECT flag.

Diagnostic Steps

  • Warning messages reported in RHEL 8:

    kernel: process Request task 22 (pid 4119) is using the deprecated raw device#012support will be removed in Linux 5.14.
kernel: process Request task 22 (pid 4119) is using the deprecated raw device#012support will be removed in Linux 5.14.
kernel: process Request task 22 (pid 4119) is using the deprecated raw device#012support will be removed in Linux 5.14.

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