Re: Unable to set group_thread_cnt [was: Re: mdadm: speedup resync process]
Hi,
On Mon, Oct 13, 2025 at 09:38:47PM +0200, Franco Martelli wrote:
> I'm unable to set "group_thread_cnt". I've added it to "mdadm.conf"
> following the syntax in the its man-page:
> …
> SYSFS name=/dev/md/0 sync_speed_max=1000000
> SYSFS name=/dev/md/0 group_thread_cnt=8
>
> and then I rebuild the initramfs image file, but after reboot only
> "sync_speed_max" is set:
>
> ~# cat /sys/block/md0/md/sync_speed_max
> 1000000 (system)
> ~# cat /sys/block/md0/md/group_thread_cnt
> 0
I've never tried doing that before.
Does /sys/block/md0/md/group_thread_cnt change if you set it manually,
e.g. with
# echo 8 > /sys/block/md0/md/group_thread_cnt
?
If so then maybe it is worth a post on the linux-raid mailing list to
ask if this is a bug in mdadm or some misunderstanding. I did wonder if
the name= was wrong (perhaps should be /dev/md0 instead) but you did say
that sync_speed_max is getting set so seems not.
In the meantime until that bit is settled, if it can be changed after
boot you can still run a script after boot to do it, right? Until more
elegant solution is found. It's not like the name "md0" should be
changing, as that is set by metadata on the devices themselves.
Thanks,
Andy
--
https://bitfolk.com/ -- No-nonsense VPS hosting
Reply to: