Skip to content
By using Twitter’s services you agree to our Cookies Use. We and our partners operate globally and use cookies, including for analytics, personalisation, and ads.

This is the legacy version of twitter.com. We will be shutting it down on June 1, 2020. Please switch to a supported browser, or disable the extension which masks your browser. You can see a list of supported browsers in our Help Center.

  • Home Home Home, current page.
  • About

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @
  • Language: English
    • Bahasa Indonesia
    • Bahasa Melayu
    • Català
    • Čeština
    • Dansk
    • Deutsch
    • English UK
    • Español
    • Filipino
    • Français
    • Hrvatski
    • Italiano
    • Magyar
    • Nederlands
    • Norsk
    • Polski
    • Português
    • Română
    • Slovenčina
    • Suomi
    • Svenska
    • Tiếng Việt
    • Türkçe
    • Ελληνικά
    • Български език
    • Русский
    • Српски
    • Українська мова
    • עִבְרִית
    • العربية
    • فارسی
    • मराठी
    • हिन्दी
    • বাংলা
    • ગુજરાતી
    • தமிழ்
    • ಕನ್ನಡ
    • ภาษาไทย
    • 한국어
    • 日本語
    • 简体中文
    • 繁體中文
  • Have an account? Log in
    Have an account?
    · Forgot password?

    New to Twitter?
    Sign up
colmmacc's profile
Colm MacCárthaigh
Colm MacCárthaigh
Colm MacCárthaigh
@colmmacc

Tweets

Colm MacCárthaigh

@colmmacc

AWS, Apache, Crypto, Irish Music, Haiku, Photography

Seattle
notesfromthesound.com
Joined April 2008

Tweets

  • © 2020 Twitter
  • About
  • Help Center
  • Terms
  • Privacy policy
  • Imprint
  • Cookies
  • Ads info
Dismiss
Previous
Next

Go to a person's profile

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @

Promote this Tweet

Block

  • Tweet with a location

    You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more

    Your lists

    Create a new list


    Under 100 characters, optional

    Privacy

    Copy link to Tweet

    Embed this Tweet

    Embed this Video

    Add this Tweet to your website by copying the code below. Learn more

    Add this video to your website by copying the code below. Learn more

    Hmm, there was a problem reaching the server.

    By embedding Twitter content in your website or app, you are agreeing to the Twitter Developer Agreement and Developer Policy.

    Preview

    Why you're seeing this ad

    Log in to Twitter

    · Forgot password?
    Don't have an account? Sign up »

    Sign up for Twitter

    Not on Twitter? Sign up, tune into the things you care about, and get updates as they happen.

    Sign up
    Have an account? Log in »

    Two-way (sending and receiving) short codes:

    Country Code For customers of
    United States 40404 (any)
    Canada 21212 (any)
    United Kingdom 86444 Vodafone, Orange, 3, O2
    Brazil 40404 Nextel, TIM
    Haiti 40404 Digicel, Voila
    Ireland 51210 Vodafone, O2
    India 53000 Bharti Airtel, Videocon, Reliance
    Indonesia 89887 AXIS, 3, Telkomsel, Indosat, XL Axiata
    Italy 4880804 Wind
    3424486444 Vodafone
    » See SMS short codes for other countries

    Confirmation

     

    Welcome home!

    This timeline is where you’ll spend most of your time, getting instant updates about what matters to you.

    Tweets not working for you?

    Hover over the profile pic and click the Following button to unfollow any account.

    Say a lot with a little

    When you see a Tweet you love, tap the heart — it lets the person who wrote it know you shared the love.

    Spread the word

    The fastest way to share someone else’s Tweet with your followers is with a Retweet. Tap the icon to send it instantly.

    Join the conversation

    Add your thoughts about any Tweet with a Reply. Find a topic you’re passionate about, and jump right in.

    Learn the latest

    Get instant insight into what people are talking about now.

    Get more of what you love

    Follow more accounts to get instant updates about topics you care about.

    Find what's happening

    See the latest conversations about any topic instantly.

    Never miss a Moment

    Catch up instantly on the best stories happening as they unfold.

    1. Colm MacCárthaigh‏ @colmmacc 28 Aug 2018
      • Report Tweet
      • Report NetzDG Violation

      Well ... it could take out nodes 1 and 4. So ❤️ is having a bad experience now. Amazing devops teams are on it, etc , but it's still not great for them. Not much we can do about that. But what about everyone else?pic.twitter.com/1J6oorA510

      1 reply 0 retweets 7 likes
      Show this thread
    2. Colm MacCárthaigh‏ @colmmacc 28 Aug 2018
      • Report Tweet
      • Report NetzDG Violation

      Well, if we look at ❤️'s neighbors. They're still fine! As long as their client is fault tolerant, which can be as simple as using retries, they can still get service. 😀 gets service from node 2 for example.pic.twitter.com/xJRpdK6Fgn

      1 reply 0 retweets 11 likes
      Show this thread
    3. Colm MacCárthaigh‏ @colmmacc 28 Aug 2018
      • Report Tweet
      • Report NetzDG Violation

      O.k. let's PAUSE for a second and appreciate that. Same number of nodes. Same number of nodes for each customer. Same number of customers. Just by using MATH, we've reduced the blast radius to 1 customer! That's INSANE.

      2 replies 1 retweet 16 likes
      Show this thread
    4. Colm MacCárthaigh‏ @colmmacc 28 Aug 2018
      • Report Tweet
      • Report NetzDG Violation

      The blast radius ends up getting really small. It's roughly proportionate to the factorial of the shard size (small) divided by the factorial of the number of nodes (which is big) ... so it can get really really small.pic.twitter.com/LmaffLA3tR

      2 replies 0 retweets 10 likes
      Show this thread
    5. Colin Percival‏ @cperciva 4 Sep 2018
      • Report Tweet
      • Report NetzDG Violation
      Replying to @colmmacc

      Surely this should be shardsize! / nodes^shardsize ? Trivial example, with 10 nodes and a shard size of 1, the blast radius is 1/10, not 1/10! .

      1 reply 0 retweets 0 likes
    6. Colm MacCárthaigh‏ @colmmacc 4 Sep 2018
      • Report Tweet
      • Report NetzDG Violation
      Replying to @cperciva

      That's a better approximation, and the real math is later in the thread, but the main take-away for people to remember is that the bigger the count of nodes relative to the size of the shard .. the better, exponentially so.

      1 reply 0 retweets 0 likes
    7. Colin Percival‏ @cperciva 4 Sep 2018
      • Report Tweet
      • Report NetzDG Violation
      Replying to @colmmacc

      Yes and no. Your formula makes it look like increasing the shard size increases the blast radius, but (up to reasonable limits) the exact opposite is true -- as long as shardsize = o(nodes) the blast radius *decreases* exponentially as the shard size increases.

      1 reply 0 retweets 0 likes
    8. Colm MacCárthaigh‏ @colmmacc 4 Sep 2018
      • Report Tweet
      • Report NetzDG Violation
      Replying to @cperciva

      I still haven't even found a great to visualize or graph it that can help people get a feel for the sensitivities. It asymptotes so quickly, but I'd really love to nail a few paragraphs that could help people reason it out.pic.twitter.com/bZ1NXEd7AM

      1 reply 0 retweets 0 likes
    9. Colin Percival‏ @cperciva 4 Sep 2018
      • Report Tweet
      • Report NetzDG Violation
      Replying to @colmmacc

      I think the best way to look at it is in terms of logarithms (or for non-mathematicians, "how many 9s"). Your blast radius is bounded from above by (S/N)^S where S = the shard size and N = the total number of nodes.

      1 reply 0 retweets 1 like
    10. Colin Percival‏ @cperciva 4 Sep 2018
      • Report Tweet
      • Report NetzDG Violation
      Replying to @cperciva @colmmacc

      So the "number of 9s of unaffected clients" > S * log(N/S); if you want 99.99% of clients to be unaffected you could have each client try 4 out of 40 nodes, or 2 out of 200, or 8 out of 8*sqrt(10), for example.

      1 reply 0 retweets 1 like
      Colm MacCárthaigh‏ @colmmacc 4 Sep 2018
      • Report Tweet
      • Report NetzDG Violation
      Replying to @cperciva

      Does the log come from Stirling's Approximation?

      1:05 PM - 4 Sep 2018
      1 reply 0 retweets 0 likes
        1. Colin Percival‏ @cperciva 4 Sep 2018
          • Report Tweet
          • Report NetzDG Violation
          Replying to @colmmacc

          Yes. If I'm remembering the formula right, for k = o(sqrt(n)), log choose(n, k) ~ k * log (n e / k) + O(log k). I dropped the k log(e) so that I could get rid of the O() term while having a strict inequality.

          0 replies 0 retweets 1 like
          Thanks. Twitter will use this to make your timeline better. Undo
          Undo

      Loading seems to be taking a while.

      Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.

        Promoted Tweet

        false

        • © 2020 Twitter
        • About
        • Help Center
        • Terms
        • Privacy policy
        • Imprint
        • Cookies
        • Ads info