Wandering Thoughts archives


A brief Exim observation

Life probably would be easier if the people behind Exim's string expansions had just been able to write a Lisp. Unfortunately that might have created some irrational prejudice against Exim, so I can see why they needed to disguise what they were doing.

(It would have been a pretty mutant Lisp. But mutating your Lisp is almost de rigueur.)

Of course, I must include a pointer to Greenspun's Tenth Rule of Programming.

programming/EximObservation written at 19:43:59; Add Comment

First irritations with Fedora Core 6

In the tradition of previous entries, some first irritations with Fedora Core 6. All of this is on an x86_64 upgrade from Fedora Core 5 on a machine with a stock configuration and stock GUI, and is mostly about the upgrade process.

  • I had to manually specify noapic on my hardware. This is not too surprising, since the regular FC5 kernels now need it, but the FC5 install kernel was fine without it.
  • at least if you have a non-RAID root device but software RAID on other devices, the upgrade process will bomb out, unable to mount them. Fortunately I did not have anything important on these partitions, so I was able to just comment them out of /etc/fstab. (On closer inspection, this is probably #188314; while my software RAID has two mirrors, I accidentally created it so that it thinks it should have three by fumble-fingering how I wanted to handle spare devices. The good news is that this won't affect my primary machine.)
  • the dependency checking phase seems really slow. There is some indication (eg #211896) that this is fixable with 'rpm --rebuilddb' beforehand, but RPM database rebuilds usually make me nervous.
  • upgrading is surprisingly slow, possibly as a side effect of the previous issue. Although I didn't time it, Anaconda claimed over 60 minutes and I can believe it.
  • the update process spends too much time looking like it has hung, with the progress bar static and the mouse cursor a plain cursor instead of the spinning 'things in progress' one. Under the circumstances, this is a bit unnerving.

The heart-stopper is what happened when I commented my LVM filesystems back into /etc/fstab and rebooted: the system screeched to a dead halt with an inability to find any LVM volumes (and complaints about /dev/hdb, the DVD drive I'd installed from, not being there). After a great deal of hammering on things, I wound up deleting /etc/lvm/.cache to fix the situation. LVM appears to use this file to cache what devices to scan, and it got reasonably mangled at some point during the upgrade, probably when Anaconda was scanning things after it failed to bring up my RAID devices.

Overall I think I like the new DejaVu fonts (and I might not have really noticed the change if not for Pete Zaitcev's potential misgivings from some time ago). The new monospaced font is makes the difference between O and 0 much clearer, although I am not sure about 1 and l. (And poor ` stays pathetically hard to see, even harder than '.)

I prefer the FC5 default background; the new one is too dim and dark for my tastes. The FC5 one may have been relatively monochromatic, but at least it wasn't dark. The login screen is especially dark and makes me feel like I'm entering a cave (given the decorations, possibly one out of a video game).

The ATI X300 I have in the current test machine finally has hardware accelerated 3D and DRI (the website says that everything through the X850 based stuff should, but I haven't confirmed that in person yet). Compiz works fine, although on an upgrade one needs to remember to do 'yum install compiz' to have it available. Mind you, some of the default effects are more glitzy than good; I recommend turning off the optional settings in System → Preferences → Desktop Effects.

Sidebar: fixing the wrong number of RAID disks in a software RAID-1

If you have accidentally created a RAID-1 array with two real drives and one spare drive by doing:

mdadm -C /dev/md0 -l 1 -n 3 /dev/foo /dev/bar missing

instead of:

mdadm -C /dev/md0 -l 1 -n 2 -x 1 /dev/foo /dev/bar missing

(like I did), the solution is pretty simple:

mdadm --grow --raid-disks=2 /dev/md0

This can safely be done to a live software RAID device.

I have to dock Anaconda points for not telling me why it was not bringing up my RAID devices, especially if it is going to later bomb out because it can't mount partitions that are using them and is going to 'corrupt' my LVM configuration when I finally get things going. A warning would have saved me a lot of time and a certain amount of heart attacks.

linux/FC6FirstIrritations written at 17:41:34; Add Comment

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