The Treehouse Blog

The desktop upgrade from Fedora 15 to Fedora 16 was about on par with the upgrade from 14 to 15.  Instead of the disaster that is Gnome 3, we’re instead greeted with GRUB 2 and new systemd quirks.

The main portion of the upgrade itself went smoothly.  No unexpected surprises from anaconda until the notice that the bootloader didn’t install right.

GRUB 2

So apparently Fedora 16 incorporates GRUB 2.  While its error messages seem far friendlier than GRUB classic, I really did not delve into all of its supposed benefits.  One downside is that when built with RAID support (which I seem to need since my /boot partition is mirrored), the core.img file ends up >32KiB, and thus does not fit in the post-MBR gap present on my drives.

To address this, I used a gparted live CD and resized and moved the first partition of each drive (which happen to be NTFS drives for my Windows 7 install, one of which was the system volume).  This provided a 2MiB gap between the MBR and first partition.  Booting back into the Fedora 16 rescue mode and using grub2-install on both drives successfully installed GRUB2 and, following a reboot, allowed Fedora 16 to load.

Unfortunately, these partition table and file system hijinks left Windows 7 with a bit of a problem, seeing as it would not boot.  The recommended method of using the Windows 7 installer’s “Startup Repair” feature was unsuccessful.  The “bootrec /fixboot” would not fix it, giving an “unsupported filesystem” error.  Using diskpart to set the Windows partition to active appears to resolve this, and the fixboot succeeds.  Naturally, I ran fixmbr at some point, which wiped out GRUB again, and thus it had to be reinstalled.  Success with booting both Windows 7 and Fedora 16 was then achieved.

NFS mount

The machine has one NFS share mounted via /etc/fstab.  After the upgrade, this would fail to mount during boot, but would have no difficulty being manually mounted after boot.  After researching a variety of wrong paths with various systemctl changes, the one I found to resolve this was “systemctl enable NetworkManager-wait-online.service”.

Update 1/8:

The upgrade of my HTPC wasn’t too painful.  Mucked with partitions to make room for GRUB2 ahead of time, had to change my lirc init script to not confuse systemd, disable screensaver in gnome 3 (yes, shouldn’t be using gnome to run mythtv – need to add that to the list), re-enabling services that weren’t automatically figured out from existing init scripts, switched mounts from /dev/md* to UUID-based to get the ordering right in the new boot sequence, mythtv ownership changes, etc, etc.

Fedora 9 to 12

Over the past few days I’ve been upgrading my file/media server from Fedora 9 to Fedora 12.  I did this with yum, upgrading from 9 to 10, 10 to 11, and 11 to 12 incrementally, removing conflicts as necessary.  This actually went surprisingly well, and at the end, with just one reboot, I had gone from 9 to 12.

It may have booted, but there were a number of things I had to fix afterwards:

• The kernel video mode setting had to be disabled to not break the NVIDIA binary driver (“blacklist nouveau” somewhere in /etc/modprobe.d/).  Apparently this is supposed to be handled by installing rpmfusion’s kmod package, but that wasn’t the case for me.
• The X server would crash immediately upon a login.  I eventually figured this out to be a missing gnome-session-xsession package.  I’m not sure if this is something I had removed for dependency reasons earlier, or if it was split from another package at some point and yum missed it.  Either way, it was a real pain to debug, but easy to fix.
• The kernel would not recognize the partitions on three of my disks.  This was a major pain, and the main focus of this article.
• I don’t like MythTV 0.22′s new video gallery

Fedora 12 (2.6.31.6-145.fc12.x86_64) Disk Partitions Issue?

So… sdb, sdc, and sde each have a single partition on them, but the kernel (per /proc/partitions and other means) would only report block devices for sdb, sdc, and sde not sdb1, sdc1, and sde1 as should have additionally existed.  Naturally, the first thing to consult would be dmesg:

sda: sda1 sda2 sda3
sdb:
sdc: sdb1
sdc1
sdd:
sde:
sdd1 sdd2 sdd3
sde1
sdf:
sdf1

At first glance, this looks really, really bad.  sdb1 existing on sdc?  That’s not supposed to happen.  But after looking at it further, and having had some experience debugging multi-threaded things, I became convinced this was the mangled output of multiple parallel partition discovery processes.  If that were the case, it looked like it should have been successful, but was not.

So, is this what happened?  Googling turned up a bit on the so-called “fastboot” patches to the Linux kernel, at least portions of which have been accepted into recent mainline kernels.  Supposedly these would only be enabled with the “fastboot” kernel parameter, but searching the source and docs for the latest kernel didn’t turn up this option.  The async libata device discovery does indeed appear to be in 2.6.31 mainline, and I was unable to find a knob to turn it off.  There were also references to this interfering with partition discovery.  I started the process of rebuilding the kernel to disable this, to see if it fixed the problem, but gave up in favor of a workaround.  I’m not fond of maintaining custom kernels – I think the last I did this was to support a boca card.

The workaround.  I had noticed that the kernel could be instructed to reread the partition tables (partprobe, for instance) and the missing partitions would appear.  I threw in a quick init script to do this and assemble the array early in the startup process:

mdadm --stop /dev/md2
sleep 1
partprobe
sleep 2
mdadm --assemble --scan /dev/md2
vgchange -ay
mount /storage

So… if I have time, I should complete that kernel rebuild and report this somewhere.  In the meantime, I’m posting this for the benefit of others.  Lucky for me the partitions affected did not contain my root partition, or this could have been less-work-aroundable.

After having been embarrased by seeing Windows Media Center have thumbnails of all video content, I found this script to populate the thumbails in MythVideo from within the video.  A lot more useful for me than the manual IMDB lookup process that I think MythVideo has natively.  Definetly spruces up the MythTV box!

I’ve had a Logitech Harmony 550 for a few months now, but I’ve only used it to replace the remote for the TV and receiver up to this point.  More recently, but still awhile ago, I bought a serial IR receiver (yeah, should have make it myself, but was lazy).  This evening I finally put the pieces together and got MythTV working with it.  Fortunately, someone already has a decent remote template and config files for the Harmony which I put to use.  Between the Harmony and the receiver, it works at almost any angle, so I’m not losing as much flexibiltiy from my RF-USB remote as I thought.

For some time now, wake-on-LAN has not been working on my home server PC.  I had been using WoL to wake the machine via a cron job on my firewall before I got home from work, and also to power the machine on remotely if I needed to get a file or such.  I had guessed a kernel change was to blame, but several updates since have not resolved, and my search for related bugs only turned up advice that didn’t work.  So, I threw in an Intel e1000 and cabled it up (using the on-board for most purposes, as the e1000 is only PCI), and WoL “just works” with the e1000.  FWIW, the on-board is an Nvidia MCP55.  Problem solved… or at least worked around.