mdadm 4.6 Released With Boot Failure Fixes, New Lockless Bitmap

Written by Michael Larabel in Linux Storage on 22 March 2026 at 09:25 AM EDT. 15 Comments
LINUX STORAGE
The mdadm utility for managing software RAID on Linux systems is out with a new release that adds new features while addressing some recent boot failure issues that were reported.

Driving the mdadm 4.6 release out the door was the desire to ship fixes for some recent boot failure reports. This includes Dracut iSCSI tests failing with mdadm 4.5 when tested on Debian. Another boot issue was the RAID array not assembling at boot with mdadm 4.5 during testing on Arch Linux. That RAID assembly issue hadn't happened with mdadm 4.4 but only regressed in version 4.5.

The mdadm 4.5 release also adds support for a new lockless bitmap feature, a new "PROBING ddf_extended" option in the mdadm.conf user configuration file, and the --detail usage option is now documented in the README.

Linux server with SSD RAID array


The mdadm 4.6 release also has fixes for an endianness issue, dealing with hot-unplugged devices in the Intel platform, optimizing DDF header search using mmap for better performance, build fixes when using the GCC 16 compiler, and other fixes.

Downloads and more details on the mdadm 4.6 release at git.kernel.org.
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Michael Larabel is the principal author of Phoronix.com and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via MichaelLarabel.com.

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