Month: November 2009

My root file system doesn’t show up in “df” anymore!

Posted on by Andy

Earlier tonight I had a strange bug report from a customer. Ever since I’d moved his VPS from one host to another, he’d stopped being able to see how much disk space he had free.

At first I thought it was simply because when I had moved his VPS I had taken the opportunity to reconfigure it to the new way I was setting them up, which meant that his root file system would be mounted from /dev/xvda instead of /dev/xvda1 (or /dev/sda1). That would have accounted for it if his monitoring tool had been doing it by device name, but it turned out that it was more fundamental than that — neither mount nor df were showing his root file system at all!

This was highly confusing at first. /proc/mounts looked correct and anyway how does a machine boot if it doesn’t know where its root file system is?

The answer to that question was a bit of a clue really: the boot loader tells the kernel what device the root file system is on, and in this case it was doing it by UUID. The UUID in the boot loader configuration was not the same as the UUID listed in /etc/fstab. I had forgotten to update the customer’s /etc/fstab. 🙁

The machine was able to boot because the boot loader was correctly configured, but then after it had already mounted the root file system it was trying to mount everything in /etc/fstab and failing on a line for a UUID that wasn’t present. That line then never made it to /etc/mtab which is what mount and df are reading from.

After correcting the /etc/fstab, it is fixable without a reboot by just mounting / again over the top of the existing one. Or you could probably just edit /etc/mtab.

Recently updated gnutls then found you can’t connect to LDAP?

Posted on by Andy

If you recently installed this update:

gnutls26 (2.4.2-6+lenny2) stable-security; urgency=high
  * Non-maintainer upload by the Security Team.
  * Fixed CVE-2009-2730: a vulnerability related to NUL bytes in
    X.509 certificate name fields. (Closes: #541439)
    GNUTLS-SA-2009-4

 -- Giuseppe Iuculano <iuculano@debian.org> Sun, 01 Nov 2009 21:29:06
+0100

and then found that your applications began failing to connect to your LDAP server, you may want to check that your SSL certificate is valid. Along with this update it seems that the default behaviour changed to being more strict. In my case I was using self-signed SSL certificates without the CA being available.

You can disable the verification if you don’t want it by adding:

TLS_REQCERT     never

in /etc/ldap/ldap.conf on each client machine.

The Bedfont Triangle

Posted on by Andy

Since moving in to this flat about 6 weeks ago, the following items have broken or started to behave oddly:

  • Humax PVR started displaying everything in a shade of pink when set to RGB output (like it always has been).
  • One of my LCD panels had its display totally corrupted with a strange tartan effect for about a day, and then went back to working perfectly again without me doing anything.
  • My hair clippers just stopped working, half way through using them.
  • My electric toothbrush wouldn’t turn off for a few minutes, then it stopped and won’t turn back on again now.
  • A brand new wall wart for a wifi access point died after 3 weeks.
  • One of the ports on my desktop switch is permanently lit up while nothing is plugged in. When you plug something in the lights go out.

Wanted: UK TV listings application

Posted on by Andy

Dear Lazyweb, do you know of a particularly good online TV listings site or application?

We don’t watch a lot of TV, but from time to time there’s some good stuff. I prefer to sit down once a week and look through what is on, save it to a list and then program it in to my PVR. At the moment I use Radio Times, but the site is often down for hours at a time. It’s rather frustrating when I’ve found time to program the PVR but the list of what I want to program is locked away inside a broken web site. The programme guide on the PVR itself is a bit cumbersome to use.

So, anyone got any good alternative sites / services?

Required features:

  • Save shows to a list, diary, whatever
  • Save shows with series link or at least to save every instance of that show name on that channel
  • Has all UK freeview channels
  • Customised channel list

Would be nice:

  • Able to dump out the list of saved shows, their times and channels so I can still program stuff even if the web site is down
  • Radio too

Radio Times fits the above requirements, but as I say it’s very unreliable. DigiGuide looks like it might be good, but it’s a Windows-only application. They say they’ve been working on a Linux version since 2007. I’m currently trying tvguide but am not sure about its “favourites” feature.

I would probably be willing to pay up to £1/month for a service that met all requirements and was actually stable. I know that TV listings data is not free to license. Anyone know how much it costs out of interest?

Wanted: photo management software for Linux

Posted on by Andy

Dear Lazyweb, what do you use for managing your photo collections locally?

At the moment I just dump them all in a directory on the file server, with Jenny’s photos in another. I used to use F-spot, which was okay, but then I wanted to store Jenny’s photos separately from my own and there doesn’t seem to be any way to do this. Is the “right” way to do it to just tag them with who took them, or what?

I don’t want to use Flickr or any other hosted service – I want to store my own photos. They are just for viewing locally – I already use Gallery2 for photos I want to publish.