Re: mdadm: speedup resync process
On Sat, 11 Oct 2025 at 20:43, Franco Martelli <martellif67@gmail.com> wrote:
> On 10/10/25 at 20:57, Greg Wooledge wrote:
> > 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.
Hi, there is a Debian package for 'htop', which is an enhanced 'top'.
It runs in console or pseudoterminal, and by default shows a bar graph
and % usage of each CPU,see screenshot here:
https://htop.dev/screenshots.html
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