Understanding "noiswmd" ARG on the kernel boot line

[boombaby]

Hello, Any...


I am a little confused (unsurprisingly) about a kernel Arg included on my Mageia-5 kernel line at boot. It is " noiswmd ".

When I search (using variations of "noiswmd" in clauses) on the Internet for simple details to understand need/requirement, the results are very sketchy. Mageia seems to use it, and Fedora might too. The connection there seems to be because both distros are RPM-based systems.

The following links MIGHT be relevant (only because they include references to "noiswmd", but are not intended for other purposes.).

https://bugs.mageia.org/show_bug.cgi?id=14330
https://linux.web.cern.ch/linux/scienti ... cal_Notes/

.
From all info I've found, it appears that " mdadm " and " dmadm " modules might also be involved.

Additionally, my understanding about those modules is that they are definitely used in setting RAID disks, but MIGHT also be needed for MULTI-disk usage/management too (ie multidisk, but NOT raided). [On that last point I am really unsure.]


Before answering it might be imperative to know three points about my system...

(A.) I do NOT have RAID (nor want it).

(B.) I DO have two HD's (containing multiple O/S's).

(C.) I DO have an old RAID-capable motherboard, but has RAID capabilities in the BIOS turned OFF.

A Note...
Many distros that I have attempted to install (or actually installed) seem to detect that I might need RAID configured, and ask if I want raid set up (or packages installed). [I'm guessing that might be because of detection of two HDs.]

Q's.
(Simple explanatory answers would be good; slightly-technical, explanatory answers are OK too.)

1.
What is " noiswmd ", and what exactly is it for?

2.
If I don't use RAID why is " noiswmd " used/needed on the kernel ARG line in my Mageia-5?

3.
I have multiple HDs, so are either "mdadm" or "dmadm" modules still needed on my system (ie even if I DO NOT use RAID)?

4.
Any other useful tips or points or guidance about this is fine.


Regards,
aka boombaby

[doktor5000]

From the upstream kernel patch for recognising this, seems it's only a compatibility shortcut for setting an option which disables dmraid/fakeraid for certain types of RAID adapters.
See the description at http://permalink.gmane.org/gmane.linux. ... ramfs/1151 which is being echoed when either rd_NO_MDIMSM or noiswmd or nodmraid is set:
"rd_NO_MDIMSM: no MD RAID for imsm/isw raids"

For some boxes this needs to be set for the partitioner to actually be able to work with the disks recognised and to be able to create partitions, from what I can tell.
See also https://bugzilla.redhat.com/show_bug.cgi?id=474049