Wolfgang S. Rupprecht wrote:
A few months ago I did a "yum -y update ; shutdown -r now". I don't know if the yum database needs a few 10's of seconds to get flushed cleanly, or what, but it got royally scrambled. A "yum list" after the reboot showed that the set of *.db files was corrupted. I could rebuild some of it from the yum cache directory, but roughly 1/3 of the rpm headers (~400) were no longer in the cache. Nuking all of fc5 would be a good way to make sure that everything in the filesystem is accounted for with no stragglers.
Yum does have some kind of database down /var/cache/yum/, but it is just holding what it last heard was available from the repos AIUI and can very safely be nuked with yum clean all and re-running yum.
RPM (yum uses the rpm libs to do the actual install/upgrade/erase) on the other hand holds a database of everything that is installed on the box, this one is down /var/lib/rpm. RPM has a longstanding bug where some kind of internal db4 database cache files, /var/lib/rpm/__db*, can get left in an inconsistent state, until these are deleted rpm then hangs or chokes. I don't know if that was the problem but with any funny behaviour from rpm that is the first port of call.
A nice shutdown like you did syncs stuff to disc and umounts your drives cleanly before restarting, being the textbook thing to do it should not have made any trouble.
I guess if it was my box I would muse about how important the data in the LVMs was to me, and take steps to back it up if it was that important. Then I would use the rescue mode method to destroy /usr, /etc and /var at least and do an "install" of FC6 (without formatting, and taking care to list your LVMs in the fdisk part of anaconda). I think that will work fine, but then my most deodorant-challenging adventures usually start that way.
past I've always bought a newer bigger disk whenever I installed a new OS. I also used to unplug the old disks just to prevent mishaps during the install.
Yes, it's a very cautious and satisfying way, especially if you find yourself installing Linux for an eager yet fretful Windows convert. Knowing they can go back makes it easier, nobody has gone back to their old drive yet though ;-) But it allows for the fact that given a random machine from a random year with a random chipset and random video, one is never quite sure how much of it Linux will be able to bring up (I take a pile of outdated but supported video cards with me), given random BIOS versions, no Internet access until the box is working again, etc. Usually it is everything important, but if you are visiting and only have limited time at least you can know for certain you can back out 100% to the old drive with 1 minute's notice. If your life isn't exciting enough trying to grapple someone else's old machine into a good Linux shape with limited time will change that!
I'm still waiting for price parity before I pick up one of the 750GB ones. They still want $100 too much vs. buying 3 of the same series drives populated with 250GB worth of heads and platters.
ACK - 750GB are not at the $/MB sweetspot where one should buy. -Andy
