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2014/04/30 3rd Supercar Drive with Club Sportiva, Long Drive
π 2014-04-30 00:00 in Cars
The last 2 times I did this, I had a great time, but like the other participants, it was difficult to appreciate the cars on the same footing and compare them when you drove them on totally different pieces of road. However, Ruch nicely agreed to do a long drive for us where we drove all 6 cars on the fun and twisty portion of the route.
This made the whole drive a bit over twice as long (and of course raised the price which is fair), and it was sooo worth it.

I think the only minus we had was being tired at the end of the day. If that's the worst that happened, it was a great day :)


drivers meeting
drivers meeting


And here are the cars I drove in sequence:

  • Lotus Elise
  • Ok, I had driven the lotus the 2 other times already, it's not a bad car, but just not my favourite. I think my worry is that if there is a patch of water around a turn, or something unexpected, the car has no means to help you (stability control). That's fine on a track where you control the environment and can't hit a tree or a bike, but on the road, I'm not a fan.




  • I then switched to the Aston Martin. It's a great touring car, but it's obviously not super nimble when thrown in turns, and what's up with the RPM gauge turning backwards?



  • The F430 was nothing new for me, but I still loved it. The sound is great, and it did great with braking and turns:

  • After 3 cars, it as time for lunch and a bit of rest :)


    And I was up for the Mercedes SLS. I expected it to be a heavy pig with a lot of grunt, but I was pleasantly surprised. It actually felt as nimble as the F430, and had more power. I actually liked it quite a bit:






  • Next, I got to try the Viper. Shifting on it is a workaround, and it scares me a bit because it has a lot of power and I don't trust the car to do much or anything to keep me on the road. The torque and grunt were just amazing, and so was the noise. It will put a smile on you while taking you to your death :)




  • And I finished with the 2013 GTR. It's definitely fast, does well around turns, and basically works no matter how badly you drive it :) It sure goes fast, but that kind of feels like cheating a bit..



  • While last year I was a bit disppointed by the shorter loop compared to my first time, this drive was awesome. We were all beat by the end of the day, and we got a real chance to try each car on an equal footing. It was well worth the time and money. Thanks Ruch for setting up this special drive for us.

    2014/04/28 Farewell To Our Cat
    π 2014-04-28 00:00 in Cats
    Unfortunately Jennifer has become more and more allergic to our cat in a way that it wasn't a good idea to keep him. On some days she'd be ok, on others not at all. At the same time the poor bugger has been needing more medical help, which I've been happy to give, and we figured we could likely keep him until his death, but recent flare ups Jennifer had made us decide otherwise.
    Because he was sick, it was not possible to give him away anywhere, but the nice lady I got him from over 10 years ago was able to get him back and will be able to care for him on his last days (including daily fluid shots, and more).

    Soon before he left, we when didn't know how much he'd live still, Jennifer wanted to give him a little tour of our yard with a made up leach. He wanted to go there, but due to racoons, poison oak he could bring home, and more, that just wasn't practical for him or us, so she gave him a supervised walk for him to enjoy the plants and grass:





    On his last day with us, I took a couple of pictures. By then he had lost a fair amount of weight already:



    After that, we had to do a full and thorough house cleaning:


    We'll miss him, he really was a good cat without an attitude and wanting nothing more than companionship, being pet, and sitting on your lap or next to you.






    See more images for Farewell To Our Cat
    2014/04/27 Cupertino Cherry Blossom Festival
    π 2014-04-27 00:00 in Public
    After going last year, we went back this year both because it was fun, and to practise for our new upcoming trip to Japan :)

    Plenty of flower art:







    And other things:










    See more images for Cupertino Cherry Blossom Festival
    2014/04/27 Btrfs Multi Device Dmcrypt
    π 2014-04-27 00:00 in Btrfs, Linux

    How to manage a btrfs filesystem made out of multiple dmcrypt'ed drives

    If you are using raid0, raid1, raid10, raid5, or raid6 with btrfs and you want your filesystem to be encrypted, you need to encrypt each device seperately but later you'll want a script to decrypt all those devices.
    This can be done with /etc/crypttab, but I don't personally use it for arrays that I turn off to save power. You can use keyscript= in there to feed a script that will provide the decryption key, but I wrote my own script to tun the disks on, locate them by disk ID, decrypt them, and mount the resulting partition.

    If you are planning on using Raid5 or Raid6, you'll also want to read this page.

    For the mount to work, you of course have to create the crypted device and filesystem first. Here is a recommended way:

    cryptsetup luksFormat -s 256 -c aes-xts-plain64  /dev/sda4
    cryptsetup luksFormat -s 256 -c aes-xts-plain64  /dev/sdb4
    cryptsetup luksFormat -s 256 -c aes-xts-plain64  /dev/sdc4
    

    cryptsetup luksOpen /dev/sda4 sda4_crypt cryptsetup luksOpen /dev/sdab sdb4_crypt cryptsetup luksOpen /dev/sdac sdc4_crypt

    mkfs.btrfs -d raid0 -m raid0 -L btrfs_pool /dev/mapper/sd[abc]4_crypt

    After reboot, the idea is to avoid the luskOpen steps and adapt to whatever device names those drives could come up under, and this is what the script below does.

    Here is the script, start-btrfs-dmcrypt, for which I'll paste a most likely outdated copy here:

    #!/bin/bash
    

    # Example script to decrypt a bunch of drives and then mount them as # part of a btrfs volume. # # By Marc MERLIN <marc_soft@merlins.org> / 2014/04/29 # License: Apache-2.0

    # Get these from /dev/disk/by-id DRIVES=" scsi-SATA_Hitachi_HDS7230_MN5220F323S79K-part1 scsi-SATA_Hitachi_HDS7230_MN5220F325UZMK-part1 scsi-SATA_ST2000DL003-9VT_5YD6MH88-part1 scsi-SATA_ST2000DL003-9VT_5YD70NHX-part1 scsi-SATA_WDC_WD20EARS-00_WD-WMAZA0374092-part1 "

    # The label name of your btrfs filesystem (mkfs.btrfs -L btrfs_pool) LABEL=btrfs_pool

    NUMDRIVES=$(echo $DRIVES | wc -w)

    die () { echo "$1" exit 1 }

    pwd="$(yourscript that returns crypt key)" if [ -z "$pwd" ]]; then echo -n "Decryption key? " stty -echo 2>/dev/null read pwd stty echo 2>/dev/null fi [ -z "$pwd" ]] && die "Didn't get a decryption key"

    # Here you can run a command to turn the disks on if they are on an # external power outlet. # turn-disks-on-cmd cd /dev/disk/by-id for i in 1 2 3 4 5 6 7 8 9 do if [ $(ls $DRIVES 2>/dev/null | wc -l) = $NUMDRIVES ]]; then break fi sleep 10 done # This is useful if the disks were just turned on. /etc/init.d/smartmontools restart

    for i in $DRIVES do dev=$(ls -l $i | awk '{print $11}' | sed "s#../..#/dev#") [ -z "$dev" ]] && die "Couldn't find device for $i" echo "$pwd" | cryptsetup luksOpen "$dev" "crypt_$(basename $dev)" || die "Couldn't decrypt $dev" echo "decrypt $dev" done btrfs device scan mkdir -p /mnt/btrfs_pool mount -v -t btrfs -o compress=zlib,noatime LABEL=$LABEL /mnt/btrfs_pool || die "Couldn't find btrfs $LABEL"

    2014/04/26 Very Late End of Season Powder Day at Kirkwood with 28 Inches of Freshies
    π 2014-04-26 00:00 in Snow
    So for those who still believe weather isn't getting more messed up, how is a super dry and crappy season that ends with 28 inches of unexplained storm (78cm) falling at kirkwood in just 24H?

    The storm didn't quite follow the forecast, it feel harder earlier and then didn't deliver friday night like it was supposed to, but by then so much had fallen that it didn't matter.
    In hindsight, Johannes and I should have arrived for Friday, noon to get some of the fresh cleaning tracks action, but eh, getting there for saturday morning, wasn't that bad.

    More people than I expected showed up, but given the forecast, it wasn't surprising:






    Unfortunately the weather got a bit warmer than it should and much of the powder was damaged by the end of the day (some even re-froze), but still, it was deep powder and good snow for the hours it lasted


    the kiddy side had been closed, so we had to ride a shuttle back to the front side
    the kiddy side had been closed, so we had to ride a shuttle back to the front side




    pretty narrow, and many rocks...
    pretty narrow, and many rocks...



    Due to ice, I slid down on top of these rocks, and jumped feet down and on my butt over the rock to land onthe other side. I got lucky, could have been worse...


    A big thanks to Johannes for getting us there and back and Jim for having us at his condo.

    2014/04/26 Btrfs Tips: Cancel A Btrfs Scrub That Is Already Stopped
    π 2014-04-26 00:00 in Btrfs, Linux

    How to cancel a btrfs scrub that won't cancel

    In some cases, btrfs scrub can be interrupted in a way that leaves it in a half state. State is stored in /var/lib/btrfs/scrub.status.UUID and if the relevant file indicates that scrub is still running (even though it is not), a new scrub cannot be started, nor the already stopped one cancelled.

    This is fixed as shown below:

    Problem:

    gargamel:~# btrfs scrub start -d /dev/mapper/dshelf1
    ERROR: scrub is already running.
    To cancel use 'btrfs scrub cancel /dev/mapper/dshelf1'.
    gargamel:~# btrfs scrub status  /dev/mapper/dshelf1
    scrub status for 6358304a-2234-4243-b02d-4944c9af47d7
            scrub started at Tue Apr  8 08:36:18 2014, running for 46347 seconds
            total bytes scrubbed: 5.70TiB with 0 errors
    gargamel:~# btrfs scrub cancel  /dev/mapper/dshelf1
    ERROR: scrub cancel failed on /dev/mapper/dshelf1: not running

    Fix:

    gargamel:~# perl -pi -e 's/finished:0/finished:1/' /var/lib/btrfs/*

    Verification:

    gargamel:~# btrfs scrub status  /dev/mapper/dshelf1
    scrub status for 6358304a-2234-4243-b02d-4944c9af47d7
            scrub started at Tue Apr  8 08:36:18 2014 and finished after 46347 seconds
            total bytes scrubbed: 5.70TiB with 0 errors
    gargamel:~# btrfs scrub start -d /dev/mapper/dshelf1
    scrub started on /dev/mapper/dshelf1, fsid 6358304a-2234-4243-b02d-4944c9af47d7 (pid=24196)
    2014/04/17 Simraceway/Sears Point Formula 3
    π 2014-04-17 00:00 in Cars
    After learning from Nico at Sears in an R8 some time back, and he more recently got me down to a 2:00 at TH (full course), it was time for me to come back to Sears and this time learn to drive their Formula 3 Cars.

    It was a 2 day school, which started with getting us used to the cars, including shifting up and down without the clutch for me. My feet were too wide and I just could not put one foot on the clutch and another one on the brakes, they didn't fit. As a result, I got to learn to downshift without the clutch by "simply" braking and revmatching with the same foot.
    We had some class time:






    Nico gave us an intro to the car
    Nico gave us an intro to the car

    Et voila, c'est facile! :)
    Et voila, c'est facile! :)

    Each car had full datalogging that the MX crew could download for us
    Each car had full datalogging that the MX crew could download for us

    The cars had a 4 cyclinder turbo engine that could be tuned up to 300hp. Lots of power for a car that weighs nothing. It can corner at 3G, more than your body tells you should be able to make a turn :)



    We did some paddocks exercises to learn oversteer and understeer control as well as downshifting under braking:


    We were a small group, just 5 of us:


    On the 2nd day, we got to drive the track untethered:

  • First session taken from GoPro:
  • Second session taken from Google Glass (better view):

  • After our last session, we got to see the data:


    What I learned was I definitely needed to hit the brakes harder, which was challenging since I also had to revmatch at the same time for downshifting. Also, I wasn't full throttle in some corners where the tires could stick but my brain wasn't used to the idea of 2G cornering yet. In the end, I was 0.25s slower than the fastest person, doh...

    To study for next time, here's a walkthrough of most corners:

    Good time was had by all, this was a great learning experience in "different" cars. Looking forward to Level 2 :)

    See more images for Simraceway/Sears Point Formula 3
    2014/04/09 Mathias' 0x28 birthday
    π 2014-04-09 00:00 in Public
    Jenny invited us all for a nice dinner for Mathias' BD. A good evening was had by all:













    See more images for Mathias' 0x28 birthday

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