Cannot change RAID array check speed

Cannot change RAID array check speed

[David Niklas]

Hello,
I upgraded my kernel from 6.9 to 6.17. They're both the "same" custom
config. I tried:

# echo 200000 > /sys/devices/virtual/block/md7/md/sync_speed
bash: /sys/devices/virtual/block/md7/md/sync_speed: Permission denied
# id
uid=0(root) gid=0(root) groups=0(root)

This used to work. Any ideas as to what I could have set wrong? I haven't
a clue!

Is there a security debugging tool or a log-file I could use to trace this
down?

Thanks,
David

Re: Cannot change RAID array check speed

[David Niklas]

I forgot to mention that I also tested with Kernel version 6.14. It has
the same problem.

Thanks again,
David

On Sun, 15 Feb 2026 22:08:43 -0500
David Niklas <simd@vfemail.net> wrote:
> Hello,
> I upgraded my kernel from 6.9 to 6.17. They're both the "same" custom
> config. I tried:
> 
> # echo 200000 > /sys/devices/virtual/block/md7/md/sync_speed
> bash: /sys/devices/virtual/block/md7/md/sync_speed: Permission denied
> # id
> uid=0(root) gid=0(root) groups=0(root)
> 
> This used to work. Any ideas as to what I could have set wrong? I
> haven't a clue!
> 
> Is there a security debugging tool or a log-file I could use to trace
> this down?
> 
> Thanks,
> David

Re: Cannot change RAID array check speed

[simd]

It worked with LK 6.9 on Devuan (Debian Stretch) ASCII.

I upgraded the system, both HW and SW, to Daedalus and I had to go with a
newer kernel to use the newer Intel iGPU. I'm now on Devuan (Debian
Bookworm) Daedalus.

I used to change this value all the time to get the check done faster or
to slow it down because I needed to access the array.

Maybe it's a distro security policy? IDK. But as I said, I used to change
it all the time. That's why there's a sync_speed_min/max, or so I thought.

Thanks,
David

PS: Accidentally sent to the user instead of to the list. Sorry.


On Mon, 16 Feb 2026 06:20:58 +0100
Dragan Milivojević <galileo@pkm-inc.com> wrote:
> When did that work?
> /sys/devices/virtual/ etc
> is readonly on 4.18,  6.12 and  6.18 (a few boxes that I have).
> 
> 
> 
> On Mon, 16 Feb 2026 at 04:15, David Niklas <simd@vfemail.net> wrote:
> >
> > Hello,
> > I upgraded my kernel from 6.9 to 6.17. They're both the "same" custom
> > config. I tried:
> >
> > # echo 200000 > /sys/devices/virtual/block/md7/md/sync_speed
> > bash: /sys/devices/virtual/block/md7/md/sync_speed: Permission denied
> > # id
> > uid=0(root) gid=0(root) groups=0(root)
> >
> > This used to work. Any ideas as to what I could have set wrong? I
> > haven't a clue!
> >
> > Is there a security debugging tool or a log-file I could use to trace
> > this down?
> >
> > Thanks,
> > David
> >  

Re: Cannot change RAID array check speed

[David Niklas]

Hey,
I think I figured this out. I need to change it via the
sync_speed_min/max. I can't used sync_speed anymore.

Thanks guys!


On Mon, 16 Feb 2026 10:14:52 -0500
simd@vfemail.net wrote:
> It worked with LK 6.9 on Devuan (Debian Stretch) ASCII.
> 
> I upgraded the system, both HW and SW, to Daedalus and I had to go with
> a newer kernel to use the newer Intel iGPU. I'm now on Devuan (Debian
> Bookworm) Daedalus.
> 
> I used to change this value all the time to get the check done faster or
> to slow it down because I needed to access the array.
> 
> Maybe it's a distro security policy? IDK. But as I said, I used to
> change it all the time. That's why there's a sync_speed_min/max, or so
> I thought.
> 
> Thanks,
> David
> 
> PS: Accidentally sent to the user instead of to the list. Sorry.
> 
> 
> On Mon, 16 Feb 2026 06:20:58 +0100
> Dragan Milivojević <galileo@pkm-inc.com> wrote:
> > When did that work?
> > /sys/devices/virtual/ etc
> > is readonly on 4.18,  6.12 and  6.18 (a few boxes that I have).
> > 
> > 
> > 
> > On Mon, 16 Feb 2026 at 04:15, David Niklas <simd@vfemail.net> wrote:  
> > >
> > > Hello,
> > > I upgraded my kernel from 6.9 to 6.17. They're both the "same"
> > > custom config. I tried:
> > >
> > > # echo 200000 > /sys/devices/virtual/block/md7/md/sync_speed
> > > bash: /sys/devices/virtual/block/md7/md/sync_speed: Permission
> > > denied # id
> > > uid=0(root) gid=0(root) groups=0(root)
> > >
> > > This used to work. Any ideas as to what I could have set wrong? I
> > > haven't a clue!
> > >
> > > Is there a security debugging tool or a log-file I could use to
> > > trace this down?
> > >
> > > Thanks,
> > > David
> > >    
> 
> 

re: Cannot change RAID array check speed

[Chris Sorenson]

>
> # echo 200000 > /sys/devices/virtual/block/md7/md/sync_speed
> bash: /sys/devices/virtual/block/md7/md/sync_speed: Permission denied
>

Wrong file; use sync_speed_min and sync_speed_max