Archive for the ‘technology’ Category

Ping localhost failed in BackupPC after Ubuntu 12.04 upgrade

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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:

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xfs v/s reiserfs storage

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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.


Add h264 support to ffmpeg on Ubuntu

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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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Making BackupPC work on Windows

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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\$

A good introductory computer book

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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/


Ubuntu One hassles

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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

Fixing Frontier’s busted DNS

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So, I have Frontier DSL service. Which means I have their ADSL service; they don’t offer a useful thing like SDSL (much like most providers). But what the do offer is DNS servers which respond to any invalid query with the IP address of one of their stupid search servers. I can’t believe that there are still ISPs out there who think it’s cool to return a result for an invalid DNS query, but I guess that’s the kind of logic that leads someone to buy Verizon’s former land line services. :/

Anyway, I run DD-WRT on my router behind the Frontier DSL router, mostly because I don’t trust any of their crap to protect my network. And I like using the embedded device as my DNS server.  Out of the box, the DD-WRT device uses DNSMasq as the DNS server (and DHCP server).  Reading the DNSMasq man page, I found that there’s an option to make it return “failed” when the upstream DNS returns a stupid search page like that.  In my case, the upstream server returns both 8.15.7.110 and 63.251.179.15 for those bad queries.

So, to fix that, you just go into your “services” main tab on the DD-WRT admin page, click on the services sub tab, and scroll down to the text box which says “Additional DNSMasq options”.  In there, paste this (substituting whatever IP you want to have trigger the “not found” response):

bogus-nxdomain=8.15.7.110

on a line by itself (you can put several lines in there, if needed, though for this you just need to pick one of the IPs returned).  Click on apply, and then test a known bad domain to see if it works.  Assuming you get “not found” now, you’ve resolved the problem; lookups which should fail, do fail.  Hooray.

While you’re in there, add a line for your local domain so it will stop asking the public DNS to resolve stuff.  Assuming you use “local.com” in your internal network (which, BTW,  means you do terrible things you should not be doing), add a line (in the same box as before) that says:

local=local.com

The wagon lives! Sortof.

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Well, I finally tracked down the reason the ABS light was activated in the wagon.  Apparently, battery voltage is one of the tests performed by the Bosch system used in the ’95 Caprice and friends.  Thanks, awesome website!  Anyway, my leaky air shocks were running the battery down and causing the low condition, even though the cool gear-reduction starter GM used on the LT1 (which, as long as you have the bigger flexplate/flywheel, you can also use on a Gen 1 smallblock or any of the big blocks, BTW) was cranking it over just fine.  So, the Battery Tender took care of that.

But I still have a problem with the transmission, and a power steering leak.  The steering leak is easy enough; I just have to replace the lines.  I’m gonna go ahead and put in the cooler return line used in the cop cars, since it has the extra loop of line which works as a steering cooler, and only costs a few bucks more.

The transmission is weird, though.  I blew the pump up a year or so ago, and just fixed it recently.  Now it runs, but what’s happening is that the computer tells the transmission to enter second, the transmission says “hey, I’m in second” – but it stays in first.  And since the shiftpoints are controlled by the road speed (which is annoying when you change tire sizes / gears / etc), you have to continue accelerating to the speed where it would normally do the 2-3 shift – except that you’re actually still in first.  So, the engine’s screaming,but the computer thinks all is fine because you’re supposedly in second.  Once it shift to third, the 3-4 shift happens as normal.

Now, I’m trying to figure out what’s going on.  I’m a tad concerned that I’ll have to pull the transmission back out an rebuild it.  But I don’t want to take it back out.  I’m considering just changing the shiftpoints to just skip second gear.  The thing makes enough torque that, with the better rear gears, I could drive it that way – or probably sell it to someone a little less mechanical.  But that’d be mean, and I’d probably feel bad. :)  So, it’ll get fixed.  Anyone with thoughts on how to do so is welcome to contact me. ;)


Testing Windows Live Writer

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I brought my Windows 7 machine (yes, I have a Windows machine – mostly for ripping DVDs) up to date this evening, and thought I’d try out the Windows Live Writer interface to see how well it works for blog editing. I don’t like the way the theme works, but I do generally like the idea of a local editing tool. So, I’ll give it a shot for a while. It’s not like I post on my blog all the time anyway. :)

Anywho, let’s see how it works…


Adding a new remote to your Dish 622

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If you have a Dish 622 receiver, or any other Dish Network receiver that uses the UHF “6.3”, it’s pretty easy to set up. but it’s apparently a pain to find the directions on the Interweb. Maybe this will make it easier to find.

All you do is fire the TV up and hit the menu button on one of your remotes twice. That should get you to the system info screen. Near the bottom, it shows the secondary remote address, and the band it’s on. Take the battery cover off of your new remote, put batteries in, and set the switch to match what the screen says (probably A unless you changed it). Put the back back on, and push the satellite button. It should light up. If not, your batteries are bad (or your ability to install batteries is bad, one of the two).

Anyway, once you’re sure the batteries are working, hold down the satellite button for a few seconds until all of the lights on the top flash once, and satellite starts blinking. Then enter the number for your address, and press pound after. I use 12, so I push 1, then 2, then #. When you press each key, the satellite button should also light up. When you hit pound, it’ll stop lighting up.  It should now be programmed to use the existing code.

You should be able to exit the menu (hit ok) with the new remote now, and the old one should still work.  If not, well, try reprogramming them.  If you hit the record button on the UHF remote while in the system info screen, the dish should switch to whatever address your remote’s set to (so you can also change it if you’re having interference issues).