partition black magic but no data lost phew!

Randi Harper randi at
Tue Jul 14 09:09:06 UTC 2009

On Mon, Jul 13, 2009 at 3:56 PM, Chris Whitehouse <cwhiteh at>wrote:

> Hi,
> This is from memory (brain not ram) and I can't recreate the steps for
> reasons which will be obvious, so may not be entirely accurate.
> I have a sata hard disk which is divided into 2 slices. Slice 1 (ad4s1) is
> about half the disk and had the remains of a standard install with swap, / ,
> /var, /tmp, /usr. Slice 2 (ad4s2) is the remainder and has a single
> partition for data, ad4s2d. It was all created with sysinstall and doesn't
> have anything special like dangerously dedicated.
> The operating system on this machine is on a second hard disk which is what
> I booted from.
> I moved all the data from ad4s1f onto ad4s2d so that I could delete
> partitions from slice 1 and make a single large partition.
> I then unmounted all ad4* partitions. I may even have rebooted.
> sysinstall - Configure - Label allowed me to delete ad4s1a but when I tried
> to delete the other ad4s1* partitions sysinstall told me I had to set
> kern.geom.debugflags=16 before I could make changes on a running system . I
> set kern.geom.debugflags but changes I made in sysinstall did not take
> effect, the partitions persisted, both as /dev/ad4s1* and as entries in
> sysinstall
> At some stage sysinstall core dumped and somewhere else ad4s2d got deleted.
> I managed to recreate it and didn't lose any data.
> Next I booted from a pen drive and successfully deleted the partitions from
> slice 1, being very careful not to delete the partition on slice 2, however
> when I exited from sysinstall ad4s2d was gone. Again I managed to recreate
> it and didn't lose any data.
> The bit that puzzles me is that ad4s2d disappeared twice and the second
> time I am sure I didn't do any explicit steps to delete it.
> Did I hit a bug in sysinstall or did I do something wrong? I didn't lose
> any data in the end but I could easily have done (I know - back up - I'm
> going to go and buy a nice big external hard disk very soon ;)
> FreeBSD muji 7.1-PRERELEASE FreeBSD 7.1-PRERELEASE #0: Mon Nov 24 20:22:16
> EST 2008 root at pcbsdx32-7:/usr/obj/pcbsd-build/cvs/7.0.2-src/sys/PCBSD
>  i386
> Everything is sorted now so I am really asking this out of curiousity.
> Thanks
> Chris
> _______________________________________________
> freebsd-questions at mailing list
> To unsubscribe, send any mail to "
> freebsd-questions-unsubscribe at"

When you booted from the pen drive, was sysinstall running as init? ie: is
this the memstick.img from the ftp site or a homebrew disc1.iso->usb image,
or did you have freebsd installed to the pen drive? If so, what version?

-- randi

More information about the freebsd-questions mailing list