[PATCH] mdadm.8: Copy --no-degraded clarification from --help output

[PATCH] mdadm.8: Copy --no-degraded clarification from --help output

[Vladimir Panteleev]

Make it easier to discover this POLA violation.
---
 mdadm.8.in | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mdadm.8.in b/mdadm.8.in
index 96846035..74cca534 100644
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -1159,6 +1159,12 @@ are present.  This is only needed with
 and can be used if the physical connections to devices are
 not as reliable as you would like.
 
+Note that "all expected drives" means as many as were present the last
+time the array was running as recorded in the superblock.  If the
+array was already degraded, and the missing device is not a new
+problem, it will still be assembled.  It is only newly missing devices
+that cause the array not to be started.
+
 .TP
 .BR \-a ", " "\-\-auto{=no,yes,md,mdp,part}"
 See this option under Create and Build options.
-- 
2.33.0

Re: [PATCH] mdadm.8: Copy --no-degraded clarification from --help output

[Tkaczyk, Mariusz]

On 29.09.2021 10:21, Vladimir Panteleev wrote:
> Make it easier to discover this POLA violation.
> ---
>   mdadm.8.in | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/mdadm.8.in b/mdadm.8.in
> index 96846035..74cca534 100644
> --- a/mdadm.8.in
> +++ b/mdadm.8.in
> @@ -1159,6 +1159,12 @@ are present.  This is only needed with
>   and can be used if the physical connections to devices are
>   not as reliable as you would like.
>   
> +Note that "all expected drives" means as many as were present the last
> +time the array was running as recorded in the superblock.  If the
> +array was already degraded, and the missing device is not a new
> +problem, it will still be assembled.  It is only newly missing devices
> +that cause the array not to be started.
> +
>   .TP
>   .BR \-a ", " "\-\-auto{=no,yes,md,mdp,part}"
>   See this option under Create and Build options.
> 

I think that it is not necessary anymore. This is default behavior,
at least for IMSM/external.
If we are using assemble with --scan then it is probably done
manually. Do we should care about unstable connections?

Normally, udev calls mdadm -I on each drive.
There is also a timer which calls #mdadm -R on array
after timeout.

I would consider to drop --no-degraded support and adapt
assemble behavior if is different.
Neil, Jes could you look?

Thanks,
Mariusz