[ug-bosug] What is the /second_root slice? How do i get rid of it?

[Manish Chakravarty]

On Feb 5, 2008 5:17 PM, Moinak Ghosh <Moinak.Ghosh at sun.com> wrote:

> Manish Chakravarty wrote:
> > Hi BOSUG,
> >
> > I did a df -h of my system and found this:
> > Filesystem             size   used  avail capacity  Mounted on
> > /dev/dsk/c2t0d0s0       15G   7.0G   7.6G    48%    /
> > /devices                 0K     0K     0K     0%    /devices
> > /dev                     0K     0K     0K     0%    /dev
> > ctfs                     0K     0K     0K     0%    /system/contract
> > proc                     0K     0K     0K     0%    /proc
> > mnttab                   0K     0K     0K     0%    /etc/mnttab
> > swap                   2.8G  1004K   2.8G     1%    /etc/svc/volatile
> > objfs                    0K     0K     0K     0%    /system/object
> > sharefs                  0K     0K     0K     0%    /etc/dfs/sharetab
> > /usr/lib/libc/libc_hwcap1.so.1
> >                         15G   7.0G   7.6G    48%    /lib/libc.so.1
> > fd                       0K     0K     0K     0%    /dev/fd
> > swap                   2.8G    80K   2.8G     1%    /tmp
> > swap                   2.8G    44K   2.8G     1%    /var/run
> > /dev/dsk/c2t0d0s4       15G    15M    15G     1%    /second_root
> > /dev/dsk/c2t0d0s7       18G   1.5G    16G     9%    /export/home
> > /dev/dsk/c1t0d0s2      3.7G   3.7G     0K   100%    /media/SOL_11_X86s\
> >
> > I did not create a /second_root slice. Why is it there and what is it
> > for?
> >
> > I dont want to waste 15 gigs of space on this slice. I want it for
> > my /export/home. Is there any way to "reclaim" it?
> >
>
>   It is meant for Live Upgrade as Saurabh mentioned in another reply.
> Essentially
>   it is a safe upgrade path. In case of a standard upgrade you boot
> from CD and
>   upgrade your root filesystem. If the upgrade fails for some reason
> your install is
>   borked! You will have to re-install. Even otherwise you might face
> problems
>   after upgrade, but going back to the previous working setup will mean
> re-install
>   again.
>
>   With live upgrade you have 2 roots. On is your active booted root,
> other is the
>   alternate root or alternate boot environment. You can clone your
> active booted
>   root onto the alternate boot environment and upgrade that while your
> system is
>   booted and you are doing other work. After the upgrade you simply
> make the
>   alternate boot environment as the active one and reboot and you will
> boot off
>   the newly upgraded setup. If you have problems with the upgraded
> setup you
>   can simply switch back to the earlier working boot environment.
>
>   This is basically a godsend for critical installations. It reduces
> chances of failure
>   and downtime. However it also means some disk space wastage. For a
> desktop
>   setup you may not want it. the simplest way to reclaim the space is
> to use ZFS.
>
>   Do this:
>
>   umount /second_root
>   umount /export/home
>
>   zpool create -f -m /export/home export_home c2t0d0s4 c2t0d0s7
>   You have all your fragmented space is one nice storage pool.
>
>   Edit /etc/vfstab and comment out the lines for second_root and
> export/home.
>
>   BTW the future direction is to move to ZFS root getting rid of this
> slicing
>   (sub-partition) business altogether. In addition one will be able to
> get the
>   benefits of Live Upgrade without having to waste disk space. The Snap
>   Upgrade project intends to use ZFS snapshot and clone features to
> provide
>   next-gen painless upgrade and boot environment administration
>

Moinak,

After i did this , i cant access my home dir "/export/home/manish" :(

Are there some other steps to be taken to mount old home dir?
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