Thursday, February 26, 2009

Stale Lock

I did a bad thing the other day and have just barely lived to tell about it. I turned of my Linux box without shutting down. All you Linux & Unix veterans know my horror when I realized what I had just done. I hit the shutdown button and, when the screen briefly blanked out before going into the shutdown graphic, I hit the power button on my power strip to turn it all off. Oh oh, says I...



Now, I never used to shut off my machine(s). The only time I have ever had a hardware problem (he says, knocking on wood), is when I was turning on a machine. Given that, and some daemons that like to run in the background at night, I usually left my computers turned on.



But I have started to get more worried about power consumption, including 'zombie' electronic devices, I have started to power down all the computers in the house before I head to bed. It makes me feel all virtuous and green. But the other night I nearly paid dearly for my greeness.



When I turn the computer on the next morning, it booted to a text screen. Somehow, I just wasn't surprised. But I couldn't figure out why. dmesg told me nothing, nor did /var/log/messages. But when I tried to 'startx', I got a complaint about .X0.lock and a "stale NFS handle". How odd, as I don't use NFS at all.



Well, this file proved to be very difficult to get rid of. See, when your X server starts up, it creates this file to prevent X from running twice. So at startup, it checks to see if /tmp/.X0.lock exists. If it doesn't, X will create it and carry on its merry way. If it does, it assumes X is already running and will complain, albeit in a very obscure fashion. The usual solution, if you're sure there isn't a X server already running, is to just delete it. But 'stale NFS handle' files are a real pain to delete, especially if they aren't really NFS handles!



I had an inkling that I needed to run fsck on the partition, but that's a problem on the root partition. Luckily, I have several other Linux partitions I can boot into, so I just booted up my openSUSE 11.1 and tried fsck from there. Haven't made the jump to 11.1 yet, as too many of my packages don't quite work right, or I don't like the newer versions (I'm talking to you, Eclipse Ganymede and Amarok 2). But fsck didn't find anything wrong either, so I was stuck for ideas.



But then I read about the force option for e2fsck, so I ran that. Voila! A few odd errors, but most especially an odd error with .X0.lock. So I mounted the filesystem while still in 11.1 and was finally able to delete the .X0.lock file. And the reboot back into my 11.0 openSUSE went swimmingly!



So the lessons learned:




  1. If X won't start, try removing the lock file found at /tmp/.X0.lock

  2. If you can't remove a file because there is a bogus 'stale NFS handle' error (and believe me, it doesn't let you do anything with it), try forcing an fsck on the partition





Wednesday, February 25, 2009

Big Bad SATA


So Best Buy had the much maligned Seagate 7200.11 Barracuda 1.5 terabyte hard drive on sale for a mere US$130. Given a couple of Best Buy rebates, I just couldn't resist picking it up for just a little of US$120 - incredible! I immediately went to the Seagate page to see if my drive had a firmware update, but luckily(?) it didn't so I was all set to install it.



Man, I just love the SATA connectors! Gone are the days of bending one of the gazillion little pins, or, even worse, getting it plugged in backwards. And no more slave/master settings either. Slid it into my tower, plugged two small cables into it and fired up the machine. It was immediately noticed and so now I needed to figure out how to partition it.



I created one 650gb partition for backups. I really truly am going to get a backup strategy implemented, especially now that my wife has her own laptop and is working from home. I'm going to run a Bacula server on my machine and Bacula clients on my box, my work box (WinXP) and my wife's Vista laptop. So I want to have plenty of room for storing select backups. I created this as an ext3 partition, with no access time tracking (for performance reasons), using YasT2's very easy Partitioner.



The other partition was a little more problematic. I want it to be the home for all our media - songs, movies, pictures. And I'll run a media server here. I have had real good luck with Mediatomb but Andrew Wafaa convinced me to try Coherence, a true DLNA/UPnP framework. It looks pretty neat - great, just what I need another project!



I wanted my media partition to be readable by WinXP as well as my openSUSE (and, in general, Linux) boots. I just checked so I know differently now, but I also thought that sharing a volume via Samba would require it to be a Windows partition as well. Turns out, that is a by now obvious bad conclusion, as Samba will share Linux partitions just fine. But as I wanted to use it natively as well, I still needed a Windows partition.



I was shying away from an NTFS partition, as I just wasn't sure how stable the NTFS-3G implementation was, so I started with a FAT32 partition. The biggest drawback with FAT32 is its 4gb max file size. It is also, I think, less efficient than NTFS in its structure, so it would use more space for such a large (nearly 750gb) partition. Once again, the Yast Partitioner worked great and was nearly instantaneous for FAT32 (or vfat) partition.



Now I wanted to move my ripped music CDs over to the new "mediax" partition (I couldn't use /media, as KDE uses that). As I wanted to preserve the time information, I used rsync:



$ rsync -auv Music /mediax
[lots and lots of]
/bin/cp: preserving times for `/mediax/Music/podcasts': Operation not permitted


That was odd. So without thinking about it too much, I decided to take the plunge and try out NTFS, as openSUSE 11 comes with read/write support "out of the box". So I reformatted it as NTFS (after rebooting into Windows, as Partitioner doesn't format NTFS) and tried again.



This time, it worked pretty well. openSUSE uses the "standard" NTFS-3G driver. There is an odd caveat about a slowdown with Amarok, my prefer music player, but it seems to have to do with writing, not reading, which I don't do much, so no big deal.



But I ran into a problem because of my change of heart. Because I had originally formated it with FAT32 (vfat) using the Partioner in YaST (openSUSE's graphical admin tool), and because Partioner doesn't support NTFS formating, I forgot to change the /etc/fstab file, so on reboot, it didn't work correctly. I then compounded errors by changing the 3rd column to being merely 'ntfs', which meant I was still getting the weird cp "Operation not permitted" error, which had me really confused. But I checked out swerdna's page on using NTFS on Linux and finally the light dawned on Marblehead. I changed the filetype to 'ntfs-3g' and now all is good and I can use my music collection whether I'm in Linux or (shudder) have to reboot into Windows.