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Ben's blog

  • ZFS send/receive accross different transport mechanisms

    Sending ZFS snapshots across the wires can be done via multiple mechanisms. Here are examples of how you can go about it and what the strengths and weaknesses are for each approach.

    SSH

    strengths: encryption / 1 command on the sender

    weaknesses: slowest

    command:

    zfs send tank/volume@snapshot | ssh user@receiver.domain.com zfs receive tank/new_volume

    NetCat

    strengths: pretty fast

    weaknesses: no encryption / 2 commands on each side that need to happen in sync

    command:

    on the receiver

    netcat -w 30 -l -p 1337 | zfs receive tank/new_volume

    on the sender

    zfs send tank/volume@snapshot | nc receiver.domain.com 1337

    (make sure that port 1337 is open)

    MBuffer

    strengths: fastest

    weaknesses: no encryption / 2 commands on each side that need to happen in sync

    command:

    on the receiver

    mbuffer -s 128k -m 1G-I 1337 | zfs receive tank/new_volume

    on the sender

    zfs send tank/volume@snapshot | mbuffer -s 128k -m 1G -O receiver.domain.com:1337

    (make sure that port 1337 is open)

    SSH + Mbuffer

    strengths: 1 command / encryption

    weaknesses: seems CPU bound by SSH encryption, may be a viable option in the future?

    command:

    zfs send tank/volume@snapshot | mbuffer -q -v 0 -s 128k -m 1G | ssh root@receiver.domain.com 'mbuffer -s 128k -m 1G | zfs receive tank/new_volume'

    Finally, here is a pretty graph of the relative time each approach takes:

    SSH + MBuffer would seem like the best of both worlds (speed & encryption), unfortunately it seems as though CPU becomes a bottleneck when doing SSH encryption.

  • That’s as close as they let me get

    2 hours tracking them, they were very very sneaky. Given that I was on a sloped terrain, I naturally went for high ground which was a mistake, they can fly away from you much faster going downhill.

    [flv:http://ben.akrin.com/wp-content/uploads/2012/10/IMG_1875.MOV.flv http://ben.akrin.com/wp-content/uploads/2012/10/thumbnail.png 688 387]

  • Heating the New England way

    Coming from the city, it totally blew my mind that you could burn wood to heat a house.

    And I totally got a toy too.

  • Turkey

    I trailed them for 90 minutes on the worst terrain (these bushy woods in the back), 2 missed shots & 1 lost arrow later, a clean shot was very rewarding. Turkeys are very elusive, getting within bow range is tough.

    Sorry buddy

  • Food reserves for the Winter

    Not enough for a family but definitely a step in the right direction. All our harvests.

  • Tunbridge World Fair 2012, ribon loot

    No “best in show” but not too shabby for a first year.

  • New toy :D

    [flv:http://ben.akrin.com/wp-content/uploads/2012/10/IMG_1786.MOV.flv http://ben.akrin.com/wp-content/uploads/2012/10/Screen-Shot-2012-10-09-at-8.58.34-PM.png 688 387]

  • MDNS/Bonjour printer discovery script

    Here’s a script I wrote whose purpose is to discover the printers that are currently being advertised by Bonjour on the network. The reason I wrote it was for a Nagios check that would in term verify that our printers were present. Writing it took me through the meanders of MDNS in Python & on Linux with multiple vlans. Let’s just say non-trivial.

    Download

    find_mdns_printers_1.0.tar.gz

    Sample output

  • Plastic foundation integration

    This is what my hack looks like as it is being assimilated by the bees.

  • Everything is back under control in the hive

    The unfortunate effect that I had in the hive by trying to fix things and enforce straight comb drawing had me pretty pessimistic about the chances of my bees this winter. Everything was completely disorganized with brood and honey in random places, way too many drones and barely any honey.

    The lesson I learned is that the hive is self healing and surprisingly so. Today’s  inspection was an amazing discovery of their capacity to adjust. They reorganized all the frames, gathered some very good honey reserves late in the season and have a very healthy population.

    And the best part is that the approach of enforcing straight comb drawing with plastic foundation every other frame worked! It’s still not an ideal scenario to have plastic in my “natural” top bar hive but it definitely takes care of the problem and I still get half of the frames 100% built by the bees.