Re: Where do I find the definitive man page for mdadm?
On Friday 12 November 2021 08:49:21 Dan Ritter wrote:
> Gene Heskett wrote:
> > The man page we have goes on and on for megabytes without ever
> > giving an example.
> >
> > I thought maybe it could scan for devices so that I could build an
> > mdadm.conf but it wont do a --scan by itself.
>
> You are looking for
>
> mdadm --detail --scan
>
> It is in that man page, as an example under --detail.
>
> > But I don't see an option (or recognize it if it is there) to give
> > it a controller id and let it make a raid10 out of the 4 identical
> > drives it could find there.
> >
> > If there is such a critter, point me at it please.
>
> You have to feed mdadm the drives you want specifically; there's
> no scattershot approach.
>
> Let's say that the drives are /dev/sdf, /dev/sdg, /dev/sdh and
> /dev/sdi.
>
> (You can re-confirm what drive is what via hdparm -i, or
> smartctl.)
>
> If you have data on them, it will be wiped out. You should copy
> off anything important, and then run wipefs on each of them.
>
> Then, creation is
>
> # mdadm -C /dev/md0 --level=10 --raid-devices=4 /dev/sdf /dev/sdg
> /dev/sdh /dev/sdi
>
> (assuming you want it named /dev/md0 and there isn't one
> already)
>
> Then you can make a filesystem on /dev/md0 and put it in your
> fstab, mount it, and copy data over to it.
>
Thats was my next Q...
> > What I'd like to do when I install bullseye, is use this raid10 for
> > the /home partition in the bullseye install.
>
> The installer will recognize it as an md RAID and can be told that you
> want to use it as-is, or you can destroy it and re-create it without
> data.
>
> -dsr-
Thanks Dan
Cheers, Gene Heskett.
--
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