Mounting a disk image, and opening an iso image, on Fedora 17

Whilst flailing around on the web, I found a couple of useful bits for mounting a disk image that contains a partition table (for example, a USB isntall image)

Firstly set up a loopback:

 losetup /dev/loop1 install.img

Then use kpartx to setup up the partitions under /dev/mapper

 kpartx -av /dev/loop1

Now the partitions can be mounted

 mount /dev/mapper/loop1p2 /mnt

As a secondary issue, opening an iso from Fedora isd easy, as long as you have the right bits installed. Under Xfce, I installed file-roller and genisoimage to open iso images.

Making libvirt shutdown guests on host poweroff

From Ask Fedora

Set the following in /etc/init.d/libvirt-guests...

ON_SHUTDOWN=shutdown
SHUTDOWN_TIMEOUT=300

Note that this is still valid in systemd at the moment (F17) as the systemd service just calls the sysv init file

Oprofile trauma on F17

Basics of using oprofile - and why fedora libraries give you no symbols

Whilst trying to profile an application, everything I did failed to give me a breakdown inside the library calls. The basic process was

sudo optcontrol --reset
sudo optcontrol --start
sudo optcontrol --dump
opreport --symbols


This failed to read symbols from system libraries. Realisation that I might need some debug symbols dawned, so added


sudo yum --enablerepo=fedora-debuginfo install SDL-debuginfo


So symbols are now available, but still not working. Finally, I blundered into this

https://bugzilla.redhat.com/show_bug.cgi?id=746823

sudo prelink -u --all


Finally, I can see where all the time goes!