Date: Sun, 11 Mar 2007 12:15:22 +0700 From: Eugene Grosbein <eugen@www.svzserv.kemerovo.su> To: "illoai@gmail.com" <illoai@gmail.com> Cc: stable@freebsd.org, Eugene Grosbein <eugen@kuzbass.ru> Subject: Re: devfs problem: creating new partition in empty slice Message-ID: <20070311051522.GA8421@svzserv.kemerovo.su> In-Reply-To: <d7195cff0703102030s38991530qcf96598223a99d8b@mail.gmail.com> References: <20070310161908.GA3238@grosbein.pp.ru> <d7195cff0703102030s38991530qcf96598223a99d8b@mail.gmail.com>
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On Sat, Mar 10, 2007 at 10:30:21PM -0600, illoai@gmail.com wrote:
> >There is FreeBSD 6.2-STABLE (updated yesterday) having single
> >SATA drive. The drive has two equal-sized slices ad4s1 and ad4s2,
> >both marked with sysid 165 (FreeBSD).
> >
> >The system occupies ad4s1 (partitions from a to h),
> >and ad4s2 is empty. This scheme was created at installation time
> >with sysinstall started by system boot CD (official disk1).
> >
> >Now, when the system is up and running, I need to create partitions
> >within slice ad4s2. Questions are:
> >
> >1. Do I really need 'sysctl kern.geom.debugflags=16'
> >if I do not want to touch MBR or living slice at all, and why, if I do?
>
> In my experience (for this type of use) no. You do not need
> to set the sysctl.
Sysinstall insists on that to proceed. Erroneously?
> >2. How should I create new partitions within ad4s2? I've tried
> >to use sysinstall, it fills bsdlabel right but fails to newfs/mount
> >new partitions because device nodes do not exist. So now I have this:
> >
> ># bsdlabel ad4s2
> ># /dev/ad4s2:
> >8 partitions:
> ># size offset fstype [fsize bsize bps/cpg]
> > a: 524288 2097152 4.2BSD 0 0 0
> > b: 2097152 0 swap
> > c: 78702435 0 unused 0 0 # "raw" part,
> > don't edit
> > d: 524288 2621440 4.2BSD 0 0 0
> > e: 4194304 3145728 4.2BSD 0 0 0
> > f: 20971520 7340032 4.2BSD 0 0 0
> > g: 20971520 28311552 4.2BSD 0 0 0
> > h: 29419363 49283072 4.2BSD 0 0 0
> >
> ># ls -l /dev/ad4s2*
> >crw-r----- 1 root operator 0, 75 10 อมา 14:53 /dev/ad4s2
> >crw-r----- 1 root operator 0, 84 10 อมา 14:53 /dev/ad4s2c
> >
> >What should I do now to get needed device nodes? The server is remote one,
> >it runs in production and I'd prefer to not reboot it.
>
> The device nodes are automagically created and managed
> on all versions of FreeBSD after 5.0.
More precisely, they should be automagically created, but they are not
in this case.
> Attemting to write to
> or read from any device node will create it (if possible) or
> chuck an error.
# true > /dev/ad4s2a
bash: /dev/ad4s2a: Operation not supported
I don't think it is not possible for devfs to create device node
but it does not. Why?
> It appears that the bsdlabel from ad4s1 is also being read,
> or has been copied to, ad4s2. You might want to
> % fdisk ad4
> and assure yourself that the slices do not overlap before
> continuing.
They do not overlap:
The data for partition 1 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
start 63, size 77593887 (37887 Meg), flag 80 (active)
beg: cyl 0/ head 1/ sector 1;
end: cyl 1023/ head 1/ sector 63
The data for partition 2 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
start 77593950, size 78702435 (38428 Meg), flag 80 (active)
beg: cyl 1023/ head 255/ sector 63;
end: cyl 1023/ head 14/ sector 63
The data for partition 3 is:
<UNUSED>
The data for partition 4 is:
<UNUSED>
By the way, I doubt that sysinstall would create overlaping slices.
And labels was not "copied". I manually duplicated partitioning
of first slice in the second using sysinstall to learn how such task
should be done in 6.x. I did not encounter such problems in 2.2.x, 3.x
and 4.x where device nodes must be created manually with /dev/MAKEDEV.
Now, either I did not read some manual (I did read recent Handbook, though)
or this is a bug.
> % bsdlabel -w ad4s2 auto
> % bsdlabel -e ad4s2
> You can probably copy and paste those above values
> if you wish,
Thanks a lot! Bsdlabel did a trick and missing device nodes have appeared.
> but putting swap in two different slices of
> the same disk is a bit . . . unoptimal.
I have no intent to use both swap partition at the same time really :-)
So I think there is a time to discover why bsdlabel leads
to automagical rising of device nodes but sysinstall does not...
Eugene Grosbein
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