On 10/10/25 at 20:57, Greg Wooledge wrote:
On Fri, Oct 10, 2025 at 20:55:38 +0200, Franco Martelli wrote:It seems to me that mdadm uses a single core during the resync process, is it possible to configure mdadm to use all the core of my CPU for the resync?That wouldn't help at all. The rebuild process is bottlenecked by I/O speed, not by your CPU.
During the last resync the system loaded the desktop (KDE), I've a CPU meter in the panel, the CPU usage reported was 10-12.5% for an eight core CPU so I thought that a single core was used at almost 100% maybe it's a coincidence, I don't know if mdadm (or the kernel) uses all the cores of the CPU for the resync process but to me seems no.
Maybe the next time, I should use a more reliable tool to measure the CPU usage (top). If I'm right I should toggle "top" to Irix mode in order to have a CPU's core usage of a single task, see "man top" and search for the string: "3a. DESCRIPTIONS of Fields"
Sorry if I insist but although it's not my case, today with SSD and NVMe devices I think that CPU's cores usage matters for a software RAID.
Thanks, kind regards. -- Franco Martelli