Wagonlicious

After upgrading my backup server from the previous LTS release (Lucid) to the new one, the config which backs up /etc on localhost was failing.  It was failing because pings to localhost were failing.  This is no good – localhost should be pingable. :)  Ultimately, this is because IPv6 is enabled by default now.  I don’t use IPv6 on my internal network, mostly because it’s new and scary and I don’t like change.  Or because I just don’t need it.  So, here’s how to disable IPv6 on your Ubuntu 12.04 / Precise box:

sauer@pyro:~$ ip addr show lo
 1: lo: mtu 16436 qdisc noqueue state UNKNOWN
 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
 inet 127.0.0.1/8 scope host lo
 inet6 ::1/128 scope host
 valid_lft forever preferred_lft forever
 sauer@pyro:~$ sudo sysctl net.ipv6.conf.all.disable_ipv6
 net.ipv6.conf.all.disable_ipv6 = 0
 sauer@pyro:~$ sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
 net.ipv6.conf.all.disable_ipv6 = 1
 sauer@pyro:~$ ip addr show lo
 1: lo: mtu 16436 qdisc noqueue state UNKNOWN
 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
 inet 127.0.0.1/8 scope host lo

Note how the inet6 address goes away as soon as ipv6 is disabled.  This will be in effect until you next reboot.  To make it permanent, you can create a file in sysctl.d and apply that (then run sysctl again just to make sure it was set):

sauer@pyro:~$ echo "net.ipv6.conf.all.disable_ipv6 = 1" | sudo tee /etc/sysctl.d/60-disableipv6.conf
net.ipv6.conf.all.disable_ipv6 = 1
sauer@pyro:~$ sudo start procps
procps stop/waiting
sauer@pyro:~$ sudo sysctl net.ipv6.conf.all.disable_ipv6
net.ipv6.conf.all.disable_ipv6 = 1

The other option is to actually configure the path to ping6 in the BackupPC config file (/etc/backuppc/config.pl) by putting in a value for Ping6Path – such as $Conf{Ping6Path} = ‘/bin/ping6′;  The default config on newer systems has that parameter set to an empty string; older installs which have been upgraded don’t even have that parameter included.

Your choice of solution will vary based on whether or not you use IPv6.  If you don’t know, then you’re not using IPv6 and can pretty safely just disable it.  Otherwise, just configure BackupPC the way it should’ve been configured to begin with.

So, since I have to rebuild my mp3 library anyway, I thought I’d do a comparison between storing my mp3s on either reiserfs or xfs.  I already know that reiserfs is horrible for recovery, but hopefully I won’t need that.  Reiser is supposed to be good for storage because of the tail-packing thing, though.

I’ve recovered about 18GB of songs now, the biggest file is about 50MB; the average is about 8MB.  Somewhat surprisingly, the xfs filesystem (/mnt/a) actually is using less space to store the identical directory structure (artist/album/mp3).

 sauer@humpy:~$ for D in /srv/nfs4/music /mnt/a;
  do find $D | wc -l; done
 1589
 1589
 sauer@humpy:~$ du -ks /srv/nfs4/music /mnt/a
 12380231        /srv/nfs4/music
 12369836        /mnt/a
 sauer@humpy:~$ df -k /srv/nfs4/music /mnt/a
 Filesystem           1K-blocks      Used Available Use% Mounted on
 /dev/mapper/idevol-music
 52427196  12414684  40012512  24% /srv/nfs4/music
 /dev/mapper/idevol-music2
 52403200  12403660  39999540  24% /mnt/a
 sauer@humpy:~$ sed -n '/music/p' /proc/mounts
 /dev/mapper/idevol-music /srv/nfs4/music reiserfs rw,noatime 0 0
 /dev/mapper/idevol-music2 /mnt/a xfs rw,relatime,attr2,delaylog,logbsize=64k,sunit=128,swidth=384,noquota 0 0

So, since xfs also recovers faster and is more actively maintained, I’m switching to xfs.

So, I’ve got a handful of Ubuntu machines.  I also have a bigger handful of DVDs.  I’d like to conver the DVDs to easier-to-store videos which can be accessed by MythTV, XBMC, my mobile devices, and whatever else easily.  The best broadly-supported format to do that in is h264-encoded mp4 files.  And DVD::Rip does a nice job of letting me use all 20 or so CPUs I have laying around, rather than limiting me to just one workstation.

Unfortunately, DVD::Rip uses transcode, which uses ffmpeg to do the encoding.  And Ubuntu’s ffmpeg, for whatever reason, lacks h264 support.  There’s a guid to rebuilding it which has you pull down the latest source for all the utilities from CVS, and make new packages which don’t work right and are a pain to maintain.  I, on the other hand, want to just take the Ubuntu package and add one compile-time option, so it’ll still work like the vendor-provided package.  After all, all I ned to do is build the exact same thing with the “–enable-libx264″ option.  Here’s how.

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So, every time I set up a new Windows system to be backed up with BackupPC, I forget what I need to change.  Thus, a blog entry.

Windows XP:

• Right-click on a folder somewhere in order to share it.  Probably the C drive.  There’ll be something indicating that file sharing is disabled.  Click through the network wizard thingie to enable file sharing.
• Create a backup user.  I prefer to call the user backuppc.  Go to the admin tools and “user and groups” to create the user, and put the user in the Backup Operators group.  Set a password, and set the password to never expire + can’t be changed.  Use the same settings for the machine-specific config inside BackupPC.
• In Administrative Tools, go to the Local Security Policy, and under User Rights Assignments, remove Backup Operators from the “Log On Locally” set (no reason for our remote backup operator to be on the log in screen). Also under Security Options, set “Network Access: Sharing and Security Model for Local Accounts” to “Classic – local users authenticate as themselves”.  The default is to access the machine as a guest after authentication, which is crazy to me (and breaks the ability for backup users to access all files in the C$ share).
• Other minor things – validate that the firewall is set to allow file sharing services in.

Test:

smbclient -U backuppc \\\\yourwindowsmachine\\C\$

This book was written by a friend of mine, so I’m biased – but it really is a good generic computer book.  And I don’t mean “generic” in the negative connotation way; rather, I mean it teaches the skills to figure out how to use a computer, rather than teaching how to use a specific program or even a specific type of computer.  It’s geared mostly toward people who didn’t grow up with a computer, and who could use something to get them a some confidence in both navigating a computer system and experimenting to find out what works.  You know, the way “computer people” probably learned.  If you or someone you know is a computer novice, this would be a good gift to follow up the computer they finally got themselves for Christmas, or whatever. :)

http://explaintechnology.wordpress.com/2011/11/28/gift-pc-primer/

Recently, I had the “this folder cannot be synchronized because it contains one or more folders that are already synchronized” problem on an Ubuntu system (midnight) which was upgraded a few times (most recent clean install was four or five releases ago).  The folder would not allow me to check the “Synchronize this folder” box most of the time, and when it did let me check the box (right-click, Ubuntu One->synchronize this folder), it wouldn’t stick.  I also had problems with the Ubuntu One frontend displaying.  I have four other Linux machines and a Windows system (mostly just for ripping my DVDs, since that software way is easier on Windows) syncing up just fine, but this one simply would not work.

Here’s what the u1sdtool command showed:

sauer@midnight:~$ u1sdtool --list-folders
Folder list:
  id=6fada2b6-4a18-48ca-951f-34092a59e4d6 subscribed=False path=/home/sauer/Documents
  id=80629790-b80b-4200-8b7e-a405842fd2ff subscribed=False path=/home/sauer/Pictures
  id=d23fed2c-042a-4862-81f7-783e9832dc71 subscribed=False path=/home/sauer/Music

Oh.  So, it knows about the folders, but doesn’t want to sync (note the “False”).  So, I just ran u1sdtool --subscribe for each of them, as in:

u1sdtool --subscribe-folder=80629790-b80b-4200-8b7e-a405842fd2ff

and it worked fine. The box in Nautilus became checked, the pop-up dialog indicated that files were being downloaded, and stuff started appearing in the folder.

Since I haven’t seen that particular solution anywhere yet, I figured it was worth tossing up on the blog.  It’s working now, and though the GUI for Ubntu One still isn’t behaving, it’s actually sync’ing files up – which is all that really matters to me on this machine.

sauer@midnight:~$ u1sdtool -s
State: QUEUE_MANAGER
    connection: With User With Network
    description: processing the commands pool
    is_connected: True
    is_error: False
    is_online: True
    queues: WORKING

So, I’ve been considering getting some original-style Chevelle SS wheels for a ’70 Chevelle. Well, technically it’s a ’71, but I like the’70 wheels.  A few companies make 15×7, 15×8 and 15×10 wheels that look like the original 14s, so I can get actual modern tires.  This post on Chevelles.com suggests that a 15×10 with 5.5 inch backspacing can fit a 295/50R15 under the stock rear wheelwell.  That’s an 11.2″ wide tire, which should be adequate. :)  I’d like to find a Firestone Wide Oval or Goodyear Polyglass or similar reproduction tire, but it looks like just running a BFG Radial T/A will be the most likely way to get that size.

Outside the Sprint store tonight, I saw a minivan blocking traffic.  So I walked over, and the kid asked if I owned the parked car he was also blocking (why he didn’t roll into a spot instead of just rolling into everyone’s way, I’ll never know).  I said “no, I’m just here to see if you need any help.”  His van had died, so I started pushing uphill.  He got out to help, because I guess he didn’t think that steering and brakes were important to the rolling vehicle.  I had it pushed back up the hill by the time he got to the back of the van – which, again, I’m not quite following.  I needed to push it backwards first, so it’s unclear what he was going to do out back.  Maybe he thought that I was making it look too easy, and wanted to make it more of a workout for me.  Anyway, I was holding the van from rolling back down the hill, and asked him to get back in, push down the brake, and turn the wheel so he could steer it into the parking spot while I used a little momentum to push it uphill again (he had come to a stop in sort of a valley).  For some reason, his reaction to my telling him three times to “push on the brake and then turn the wheel” was to turn the key to start it.  This was yet another entry in the list of incomprehensible things he did – but strangely, the van started right up.  So, he’d been sitting there confusedly blocking traffic (well, not quick blocking – people could drive around, albeit inconveniently) for at least 10 minutes.  He was occasionally turning his reverse lights on and randomly mashing the brake, but it seemingly hadn’t occurred to him to attempt to turn the key.

Oh well.  He got the car running, I did my good deed, and the people who were annoyed at him would have probably been annoyed at something else later anyway.  So I left and went home.  I don’t know if he got his coffee or if the van started afterwards.  I do know that the Mexican cleaning lady I helped (her brakes went out on her way to work and she stopped the van by ramming into a pile of snow right in front of me) last winter – the one who spoke about four words of English – was better at following directions and explaining her problem…