Date: Sun, 20 Mar 2011 18:34:44 -0400 From: Maxim Khitrov <max@mxcrypt.com> To: FreeBSD <freebsd-questions@freebsd.org> Subject: Re: glabel causes "GEOM: ada1: media size does not match label" messages Message-ID: <AANLkTik7C-RNLN09WzL67DOkmb_N_y3J2iDSx9fsoQGK@mail.gmail.com> In-Reply-To: <AANLkTi=bEcXjKkY6Rpv6ECHyt4qSA0KBDJ-z0VB_CJ6z@mail.gmail.com> References: <AANLkTi=bEcXjKkY6Rpv6ECHyt4qSA0KBDJ-z0VB_CJ6z@mail.gmail.com>
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On Sun, Mar 20, 2011 at 4:38 PM, Maxim Khitrov <max@mxcrypt.com> wrote: > Hi all, > > Executing the following commands on any valid storage device seems to > cause "media size does not match label" kernel messages (FreeBSD 8.2 > amd64). I understand why they happen - glabel metadata occupies the > last sector, so bsdlabel sees a device that is 1 sector smaller than > what the kernel sees. The question is whether there is some simple way > of suppressing these messages, since they come up every time the > system is booted or the partition is mounted/unmounted: > > # glabel label vol0 ada1 > # bsdlabel -w /dev/label/vol0 > GEOM: ada1: media size does not match label. > # newfs /dev/label/vol0a > # mount /dev/label/vol0a /mnt > GEOM: ada1: media size does not match label. > # umount /mnt > GEOM: ada1: media size does not match label. > > As you can see, I'm not using MBR or GPT partitioning schemes. I try > to avoid those unless I plan on sharing the media with another OS. > Even if using gpart would get rid of these errors (not sure, since > then you'll just have a partition whose size doesn't match), I would > still prefer to find some other way to suppress them. > > - Max > Heh... In the process of searching for a solution to this, I decided to see what would happen if I used bsdlabel on ada1 rather than vol0 (in my example above), and created a 1-sector partition at the very end of the disk. So the layout would be something like this: # /dev/ada1: 8 partitions: # size offset fstype [fsize bsize bps/cpg] a: * * 4.2BSD c: * 0 unused h: 1 * unused The 'c' partition now covers the entire disk, which stops the kernel from complaining about media size not matching the label. At the same time, the 'h' partition will protect the last sector, which contains glabel metadata. The problem now is that the label is technically invalid for the vol0 device, which is what I'll be mounting. Indeed, bsdlabel complains when I run it for /dev/label/vol0: # /dev/label/vol0: 8 partitions: # size offset fstype [fsize bsize bps/cpg] a: 3907029151 16 4.2BSD 0 0 0 c: 3907029168 0 unused 0 0 h: 1 3907029167 unused 0 0 partition c: partition extends past end of unit bsdlabel: partition c doesn't cover the whole unit! bsdlabel: An incorrect partition c may cause problems for standard system utilities partition h: partition extends past end of unit I don't care about partition 'h'; it is there only to stop the preceding partition from covering the last sector. Are there any real issues with the 'c' partition being 1 sector too big for the vol0 device (but just the right size for ada1)? This is a bit of a hack, but I'll take it if it stops the kernel from complaining and doesn't create any new problems. - Max
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