[dm-devel] [PATCH 16/16] multipath: update man pages

[Martin Wilck]

On Fri, 2019-08-02 at 11:33 -0500, Benjamin Marzinski wrote:
> Add documentation for the marginal_pathgroups option and the
> (un)setmarginal commands.
> 
> Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
> ---
>  multipath/multipath.conf.5 | 34 ++++++++++++++++++++++++++++++----
>  multipathd/multipathd.8    | 19 +++++++++++++++++++
>  2 files changed, 49 insertions(+), 4 deletions(-)
> 
> --- a/multipathd/multipathd.8
> +++ b/multipathd/multipathd.8
> @@ -277,6 +277,25 @@ Remove the persistent reservation key associated
> with $map from the
>  \fIreservation_key\fR is set to \fBfile\fR in
> \fI/etc/multipath.conf\fR.
>  .
>  .TP
> +.B path $path setmarginal
> +move $path to a marginal pathgroup. The path will remain in the
> marginal
> +path group until \fIunsetmarginal\fR is called. This command will
> only
> +work if \fImarginal_pathgroups\fR is enabled and there is no Shaky
> paths
> +detection method configured (see the multipath.conf man page for
> details).

This is counter-intuitive. It's unclear to me why we need these
commands at all. By nature of "shaky" paths, it doesn't make a lot of
sense to make these settings (only) manually. I'd like it better if the
cli commands somehow hooked into the different "shaky" algorithms. E.g.
for the san_path_err_ algorithm, setting a path to marginal would mean
artificially setting its failure count to a value above the configured
threshold. That way, the manual settings could work togehter with the
automatic detection methods, and could be used for overriding them
in special cases.

Martin