[linux-lvm] N00b Question: Logical Volume without a Logical Volume Group ?

[Dan White]

----- Dan White <ygor at comcast.net> wrote:
> ----- James Hawtin <oolon at ankh.org> wrote:
> > Dan White wrote:
> > >
> > > I just experienced that.
> > >
> > > I had to reboot the machine to "see" the expanded LUN.
> > > I used fdisk to make a partition out of the LUN expansion, but I had to reboot again before I could do anything further.
> > > After the second reboot, I was able to make a PV out of the new partition, roll it into the existing VG and then expand the two test LV's I had previously created to utilize the new elbow room.
> > >
> > > This is on a RHEL 5.7 system.
> > >
> > > Is there a way to do this without the rebooting ?
> > >
> > >   
> > Assuming the device is sda then
> > 
> > |echo 1 > /sys/block/sda/device/rescan|
> > 
> > However if that fails (and it can) only a reboot or removing the disk 
> > driver module and reinstalling it will scan it correctly (possible if 
> > you have a mix of local and san disk) however probably a reboot is easiler.
> > 
> 
> OK.
> How about the addition of a new LUN ?
> 
> A new device (/dev/sdb) should "appear", but I'd like to do it without rerbooting.
> 

!! Found the answer myself !!

echo "- - -" > /sys/class/scsi_host/hostX/scan 

where "X" is the controller you want to refresh.  On my system, I see host0 thru host5 in /sys/class/scsi_host/, so I did all 6 and /dev/sdb appeared.  I was able to roll it into my volume group with system-config-lvm.

Wahoo !!

“Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.”
Bill Waterson (Calvin & Hobbes)