Cloudflare DNS Broke on Several of Their Systems Because Programmers Assumed Time Couldn’t Move Backwards… Then It Did…

nbeam published 7 years ago in Cloud Services, Programming.

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Apparently a handful of customers using Cloudflare for DNS, and specifically CNAME records experienced a brief outage of name resolution services on New Year’s. I found the reason why to be rather interesting. Devs at cloudflare assumed time can’t move backwards… An understandable assumption but actually faulty because of leap seconds… Anyhow, if you do programming you might find the root cause analysis for this hiccup to be interesting and informative:

https://blog.cloudflare.com/how-and-why-the-leap-second-affected-cloudflare-dns/

Well worth a quick read. No, unfortunately it didn’t have anything to do with Dark Matter and/or what happens were a black hole and a Delorian traveling at 88 mph suddenly to meet while Superman flies around the planet at light speed. But, it is still curious enough all the same. Happy New Year… Sanitize your outputs…

Splitting up the MSSQL TempDB into Multiple Files Spread Across Multiple Drives

nbeam published 7 years ago in Database Administration, Microsoft. Tags: ,

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Without going into great technical detail (which on this topic I couldn’t do anyway), it seems after much reading that it is a recommended practice to spread you SQL Server TempDB across multiple files based on how many cores (or perhaps threads) your processor has.

To keep things simple, let’s say I have a 4 core CPU and no hyper-threading (I am not sure if the rule applies to physical cores or to threads), this means I want to split my TempDB up into four different files. However there is one caveat, you should only do this if you actually have four separate physical drives. Not separate files on one drive, not even separate files on separate partitions… this is only beneficial if you actually have separate physical drives based on what I read.
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Brief Snippet – How to Send Emails from the Powershell Command Line

nbeam published 7 years ago in Microsoft, Powershell. Tags: ,

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I have been working on email stuff on and off for the last… forever.

One of the very handy and easy to use tools to have in one’s pocket for testing email functionality with a particular SMTP server is the ability to quickly send email through a selected server from the command line. Just like using telnet to test ports makes day-to-day IT life easier vs. having to grab and install some extra tool, so also does the ability to shoot emails off from a CLI.
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Setting up a SQL Server 2012 Failover Cluster with a Dell Equallogic SAN

nbeam published 8 years ago in Database Administration, Microsoft, Server 2012R2, Storage, Windows Administration. Tags: , , ,

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I have been fiddling about with setting up a SQL Server 2012 Failover cluster using an Equallogic SAN. After a whole lot of digging about I found two different posts on two different sites which got me about 90% of the way there. However there were some key “gotcha’s” and other information that was missing in both cases and I wanted to document those here in addition to referencing the articles I followed for my setup.

BTW – Just my 2-cents, but setting up clustering is complicated… especially when you throw SQL in the mix. It isn’t bad once you have done it a few times (I tested again, and again, and again in a virtual environment) but there are honestly like 50+ considerations to take into account to ensure everything goes correctly.

I am assuming if you are here you already have a general understanding of failover clustering, know what you are wanting to do and why. This article also doesn’t really cover all aspects of high-availability. I don’t discuss how your SAN(s) should be networked for example. I do touch on a few items though that fall in this area. This isn’t meant to be comprehensive and a lot of it is just for personal reference.

So here are some tips if this is your first go around. These are in NO particular order or grouping (this is very “stream of thought”) so I would suggest reading this from start to finish at least once rather than referencing it as you are going through your setup.
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Dealing with Layer-1 – 10 Gig Networking – SFP, SFP+, 10GBe Base-T, TwinAx, Optical Fiber, Transceivers, Oh My!

nbeam published 8 years ago in Networking. Tags: , , , , , ,

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Currently I am working on integrating some 10Gbe switches into an existing 1Gbe network. Being completely new to 10 Gbe I wasn’t prepared for the volley of new terms, acronyms, and gotcha’s that were thrown my way.

Initially I had a very hard time finding answers to some basic questions. So I figured I would write a quick post for everyone else having the same struggles… Excuse my laymen explanations and gross oversimplifications which are to follow… To some I may sound the dunce, so be it. I hope this is helpful to all the other dunces :).
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