Date: Wed, 7 Feb 2007 22:36:40 +0100 From: "Simon L. Nielsen" <simon@FreeBSD.org> To: Ivan Voras <ivoras@fer.hr> Cc: freebsd-geom@freebsd.org Subject: Re: New g_part class Message-ID: <20070207213640.GB988@zaphod.nitro.dk> In-Reply-To: <eqdfjm$5c3$1@sea.gmane.org> References: <45C98F32.20308@enderzone.com> <99017.1170839681@critter.freebsd.dk> <eqdfjm$5c3$1@sea.gmane.org>
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On 2007.02.07 22:16:38 +0100, Ivan Voras wrote:
> Poul-Henning Kamp wrote:
>
> > You mean writing to sectors which mounted filesystems belive they
> > have exclusive use of ?
> >
> > No, GEOM doesn't support or allow that.
>
> Ok, the need for sysctl kern.geom.debugflags=16 arises because the live
> system to be used as master has mounted partitions, and those partitions
> span the whole disk, thus conflict with gmirror which wants to use the
> last sector. Since using the last sector for metadata is The Official
> Way, how about making such conflicts easy to avoid, like for example
> building additional logic in g_part to create partitions one sector
> smaller than the container?
Eh, gmirror already does the right thing... :
[root@eddie:simon] gmirror status gmd0
Name Status Components
mirror/gmd0 COMPLETE ad18
ad20
[root@eddie:simon] diskinfo -v /dev/mirror/gmd0
/dev/mirror/gmd0
512 # sectorsize
200049647104 # mediasize in bytes (186G)
390721967 # mediasize in sectors
[root@eddie:simon] diskinfo -v /dev/ad18
/dev/ad18
512 # sectorsize
200049647616 # mediasize in bytes (186G)
390721968 # mediasize in sectors
387621 # Cylinders according to firmware.
16 # Heads according to firmware.
63 # Sectors according to firmware.
IE. the gmirror device is one sector smaller than the disk device.
--
Simon L. Nielsen
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