Re: Where do I find the definitive man page for mdadm?
On Friday 12 November 2021 11:57:28 Andrew M.A. Cater wrote:
> On Fri, Nov 12, 2021 at 09:48:01AM -0500, Gene Heskett wrote:
> > 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
> >
> > Null return on stretch version of mdadm. Supposedly up to date as of
> > an hour ago.
> >
> > > It is in that man page, as an example under --detail.
> >
> > Not in the stretch man page. And its sounding as if I should do
> > that during the bullseye install to get the more capable mdadm, but
> > will the devices have the same names? With the reputation for
> > volatility of device names a mistake there could destroy 23 years of
> > data.
> >
> > > > 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.
> >
> > So mkfs.ext4 /md0 is required, ok
> >
> > > > 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.
> > --
> > "There are four boxes to be used in defense of liberty:
> > soap, ballot, jury, and ammo. Please use in that order."
> > -Ed Howdershelt (Author, 1940)
> > If we desire respect for the law, we must first make the law
> > respectable. - Louis D. Brandeis
> > Genes Web page <http://geneslinuxbox.net:6309/gene>
>
> Gene
>
> At the point when you want to install Bullseye:
>
> Use an expert install.
>
> set up the disks as RAID 10 first, then use the partition editor to
> assign the RAID as /home
>
> At that point, you're done :)
That will be good, but getting rid of the first raid10 I built is needing
tactical nukes. Its taking almost 40 minutes a drive to zero them and
start over. And this machine is acting like an 8086 machine doing it.
very very slow. gkrellm is showing all 6 core in bright orange. Not any
great temp rises though, staying below 35C for all 6 cores. The heat
sink/radiator is huge, so huge I can't put the side panel back on the
tower. 5" fan is turning silently at maybe 400 revs. I think I overbuilt
it ;o)
> All the very best, as ever,
Of coarse, to you too Andy. Stay well.
> Andy C.
Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>
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