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2011/04/30

Fedora 14 could not find root filesystem on RAID-1 array, solution

Filed under: — Stormwind @ 8:45 am

Here’s a problem I ran into recently: I temporarily switched the root filesystem of my Fedora 14 install from RAID-5 to non-RAID. After I received the new SSD drives, I switched it to RAID-1 but the dracut boot sequence could not find the RAID-1 array and mount the root filesystem, ending in the errors ‘Can’t mount root filesystem. Boot has failed, sleeping forever’.

Using the dracut rdshell and rdinitdebug kernel boot options to get a shell prompt from the dracut initramfs led me to the RAID assembly failing during boot during “dracut: Autoassembling MD Raid”. I discovered manually assembling the array using mdadm –assemble … then exiting the shell would allow the boot to continue, so at least I had a temporary workaround.

To fix the dracut auto assembly of the RAID array, I did the following:

  1. Booted up a Fedora Live CD so I could manipulate the RAID partitions without them being mounted/used (since they contained the root filesystem).
  2. After noticing that the volume type was wrong on one of the RAID-1 member partitions by running blkid (TYPE was not “linux_raid_member”) and making sure the other partition was up-to-date with the data, I used wipefs (remember to use the -a option) on the partition with the incorrect data (and let the next step sync the data from the correct partition).
  3. Set the system hostname via the hostname command, then did “mdadm –assemble /dev/md1 /dev/sda2 /dev/sdb2 –update=name –update=uuid”. This fixed the array name to be hostname:1.
  4. After booting the system back up normally with the workaround, made a backup of /etc/mdadm.conf then did “mdadm –examine –scan > /etc/mdadm.conf” and made sure /etc/mdadm.conf looked correct afterward.

After these steps, the dracut boot sequence was able to auto-assemble the RAID array on boot and mount the root filesystem.

I hope this writeup helps someone who runs into a similar problem. ūüôā

2011/04/29

nut 2.6.0 not working with USB CyberPower System UPS, fixed in trunk

Filed under: — Stormwind @ 6:13 pm

Have a USB-attached CyberPower System UPS but can’t get it to work with Network UPS Tools aka nut 2.6.0 (such as from the Fedora 14 or 15 rpms)? See the link to the rpms below I built.

The errors you might see (especially when running usbhid-ups -D -D -D) include “could not connect to ups”, “libusb_get_report: error sending control message: Operation not permitted”, and “Can’t retrieve Report 03: Operation not permitted”.

There is a workaround for a libusb issue affecting communication with USB CyberPower Systen UPSs in the trunk branch of the nut source code that will get into nut 2.7, but was not part of nut 2.6. See the fix here in change 2893 on nut’s trac system. Read more about the problem in this message on nut-upsuser.

To get the fix now (before the 2.7 rpms are released), I rebuilt nut 2.6 rpms (with small changes to the spec file) using the latest source snapshot from nut’s buildbot, r2978. You can download these r2978 rpm’s from here.

2011/01/17

Hacking the Neato XV-11 robotic vacuum cleaner

Filed under: — Stormwind @ 8:50 pm

Have a Neato XV-11 robotic vacuum cleaner with an intriguing USB port?

Check out Hash’s post at the Random Workshop about connecting to the XV-11’s built-in serial subsystem via USB to send and receive commands and data from the vacuum. ¬† I’m using a Linux box and minicom. ¬†ūüôā

Now I just need a miniature embedded Linux platform with wifi so I can wirelessly communicate with the robot while it vacuums so I can try to create images from the LIDAR data as it maps the house…

2010/12/26

Fedora 12 to 14 Upgrade

Filed under: — Stormwind @ 11:17 am

I upgraded Fedora 12 to Fedora 14 over the weekend using PreUpgrade for the first time.   (I tried a direct yum distro-sync upgrade first but it got stuck in infinite dependency loops.)

Overall I was impressed with the download size reduction and the install speed after rebooting the system for the anaconda installer to apply the new packages.  I liked the reduction in system downtime resulting from downloading all the packages before the reboot and the smaller set of packages that were installed.

Some extra steps I had to deal with:

  1. There are a couple bugs in the version of PreUpgrade that is part of Fedora 12.   This post on The Wily Blog contains the fixes to the preupgrade-cli script needed for it to run.
  2. preupgrade-cli needed /etc/sysconfig/i18n to exist but it was missing on my system.   I created the file with the default values from the Fedora docs to get past this issue.

It also seemed like the install asked a few redundant questions it could have figured out before the reboot to start the install:

  1. The installer asked whether to do a fresh install or an upgrade, where a PreUpgrade is obviously an upgrade.
  2. The installer asked which filesystem’s installation to upgrade (there was only one on the system), and then again asked which filesystem to add to the “upgrade” list. ¬†I believe it could have assumed the same filesystem for both questions, and even possibly set default values for all of them based on the filesystems in use when PreUpgrade was run before the reboot.
  3. The installer asked which interface provided the internet connection for downloading additional packages and images, which PreUpgrade could have figured out before the reboot and passed it along.

This upgrade was the most painless Fedora or Red Hat upgrade I’ve done in years! ¬†Almost all of my services worked afterward with no reconfiguration. ¬†A big thanks and hats off the the Fedora team for PreUpgrade!

2010/10/23

Chevy Volt test drive

Filed under: — Stormwind @ 11:34 am

At the Chevy Volt test drive, waiting in line…

2010/06/14

Zero Energy Casita in Fort Worth

Filed under: — Stormwind @ 7:32 am

Inhabit posted a story about a net-zero energy small house (1,051 sq ft) built recently in Fort Worth:

Zero Energy Casita in Texas Opens to the Public | Inhabitat – Green Design Will Save the World.

2010/06/12

Our Home Efficiency Improvements

Filed under: — Stormwind @ 8:50 pm

Lisa and I recently went on the Austin Cool House Tour co-sponsored by the Texas Solar Energy Society and Austin Energy Green  Building.

We realized the efficiency retrofits to our home were pretty similar to what we saw on the tour, so for fun I thought I’d write up the green feature list of our house in the same format as used by the tour book.

Home Solar Plant - Small

Spangler Home – Northwest Austin

Built as a traditional non-green building, this Austin home has been retrofitted for energy efficiency and simple but high-tech living.

Owners: Lisa and Jason Spangler
Solar PV: Texas Solar Power Company

Green Features

  1. 10KW grid-tied solar photovoltaic array (by Texas Solar Power Company)
  2. Whole-home energy monitor (TED 5000).
  3. White reflective metal roof (Sheffield Metals CoolR Solar White Galvalume – Reflectivity 0.68, Emissivity 0.85, SRI 82, 25% recycled content, 100% recyclable – installed by Southwest Metal Roofing Systems).
  4. Level 2 EVSE (electric vehicle car charger) and a Chevy Volt range-extended electric car
  5. Lawn replaced with native plant and prairie garden which requires almost no supplemental watering.  Crushed granite and limestone paths allow water penetration.  Mature trees provide shade.
  6. R-38 insulation in attic with R-8 ductwork.  R-9 garage door insulation.
  7. 1 gpm low-flow showerheads (from New Braunfels-based Bricor).  Shut-off values on showers for optional Navy shower.
  8. Solar screens on all windows.
  9. Energy Star appliances from the highest CEE efficiency tier (dishwasher, refrigerator, clothes washer and dryer).  Energy Star electronics.
  10. 19 SEER multi-zoned HVAC system with variable speed motor and fan coils, and programmable thermostats.
  11. All lighting is CFL or LED.  (LED fishtank and main kitchen lighting reduces energy usage of most-used lights.)
  12. High efficiency aerodynamic ceiling fans with timed remotes throughout.  (Gossamer Wind fans)
  13. Masonry and fiber cement siding  and trim (Hardiboard).
  14. Ethernet networking (Cat6) and high speed Internet connection enables telecommuting to save energy and reduce emissions.  Energy-efficient computers. Notebook and Home theater systems that sleep when not in use.
  15. Weather station (Davis Vantage Pro2 Plus)
  16. Easy access to transportation – bike lanes, public transportation (bus stop 0.4 miles away), two light rail stations nearby (4.0 and 5.2 miles).

Any other ideas for increasing energy efficiency or going more green?  Leave the in the comments!

Update: Here is an aerial photo of the metal roof and solar panels from Google Maps:

2010/05/04

DNS partially break under Fedora 12 recently?

Filed under: — Stormwind @ 3:23 pm

Did DNS partially break under Fedora 12 32-bit or x64 on your machine recently?

It was the strangest thing…¬† DNS problems started for me last week, even though I had not done any software updates since the beginning of April.¬† Machines using my caching nameserver would be fine, but some programs running locally would fail all name resolves (while others would succeed).

After much pulling of hair, gnashing of teeth, and searching of Google, I eventually ran across a bug entry and comment that helped with the following instructions:

  1. yum install nss-mdns
  2. Change the hosts line in /etc/nsswitch.conf to “hosts: files mdns4_minimal dns”

And name resolution is back! ūüôā

2010/01/24

When Software Kills…

Filed under: — Stormwind @ 10:22 am

Buggy software played a part in radiation overdoses given to some cancer patients, leading to deaths.

The Radiation Boom – Radiation Offers New Cures, and Ways to Do Harm – Series – NYTimes.com.

2009/08/18

Speaking in September

Filed under: — Stormwind @ 1:39 pm

I’ll be speaking at two game development conferences during September: CEDEC 2009 in Japan and GDC Austin in Texas.¬† Details and links follow.

CEDEC 2009 – CESA Developers Conference 9/1 – 9/3 in Yokohama, Japan

  1. Handling Code and Assets for Huge Projects Using State-of-the-Art SCM
  2. What I Have Learnt From Japan (panel) – Tuesday 9/1, 11:20 – 12:20

GDC Austin (Game Developers Conference) Р9/15  Р9/18 in Austin, TX

  1. Defending the Realm: Resisting Exploits and Hacks to MMOs and Other Online Games (roundtable)- Thursday 9/17 3p-4p

Look me up and say hi if you are there!

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