Windows is better than Unix/Linux. Now that I’ve incited volumes of hatred from my Unix/Linux brethren, let me clarify my stance. I work with massively heterogeneous environments. For the past 10 years, every company I’ve supported has utilized at least 3 different operating system platforms including multiple versions and flavors of Linux, Unix, Windows, with some mid-frame (As/400) and Novell thrown in for good measure. The experience has taught me to choose the best tool for the job, rather than get religious about a platform. There are many functions that Windows performs better than *nix, and the *nix community should embrace them.

I hire a lot of Unix/Linux sys admins. One of my favorite interview questions for them is: “Name 5 ways Windows is better than Unix/Linux.” This is a great stress question, because most *nix guys think Microsoft is the devil. But Microsoft remains the most successful software company in the world. If you cannot recognize the areas where Microsoft excels, you are artificially narrowing your view of the world, which means you aren’t making the best technology decisions for your company, which means you can’t work for me (To be fair, I also ask Windows guys to name ways Unix/Linux is better than Windows). As a public service to *nix admins everywhere, I offer this list of 5 ways Windows is better than *nix. There are many others, but I don’t want to overwhelm you with too much info at once. It might overload your system, and cause a kernel panic.

1. Windows XP is the best productivity desktop
2. Windows 2003 Active Directory Service is the best directory service
3. Windows DNS is the best internal DNS server
4. Exchange 2007 is the best groupware application platform
5. Windows has better hardware support with vendor-supported drivers

Let the flame wars begin! Seriously though, I stand by each of those pronouncements. For those of you who haven’t run screaming from the room, my reasoning is below: (read more…)

I’ve spent the past few days trying to develop a simple mathematical model to predict the expected availability of complex systems. In IT, we are often asked to develop and commit to service level agreements (SLAs). If the points of failure of the system are not analyzed, and then the system availability calculated, the SLA is flawed from the beginning. To complicate matters further, different people have different definitions of availability. For instance, does scheduled downtime for maintenance count against your system availability calculation?

Common Availability Definitions:

1. Availability = MTBF/(MTTR+MTBF) (Mean Time Between Failure, Mean Time To Recover). This is a classic definition of availability and is often used by hardware manufacturers when they publish an availability metric for a given server.
2. Availability = (Uptime + Scheduled Maintenance)/(Unscheduled Downtime + Uptime + Scheduled Maintenance). This is an IT centric availability metric where the business can support scheduled downtime after hours. This model works for some types of systems, such as a file server that isn’t needed at night, but it doesn’t work as well for websites, even though many web companies still use this for their SLAs.
3. Availability = Uptime/(Uptime + Downtime). This metric best applies to systems that are needed 24×7 such as e-commerce sites.

Availability is most often expressed as a percentage. Sometimes, people will refer to “four nines” (99.99%) or “five nines” (99.999%). To simplify things, the following table shows the minutes of downtime allowed per year for a given availability level:

(read more…)

My new job with StubHub came with a host of excellent benefits, including a shiny, new 401K with Charles Schwab. Schwab is generally known as a good, stable company with a strong online presence, so I was shocked by what arrived in the mail today. About a week after signing up for my 401K, I received a letter from Schwab titled “Confirmation of Personal Identification Number Change,” and right below the subject line is the password I had chosen for the website! To make matters worse, the letter came in an envelope from Charles Schwab labeled “Personal and Confidential,” ie. “STEAL ME.”

This letter got me thinking about all the supposedly strong security mechanisms employed by various online companies that I deal with that just make matters worse. The schwabplan.com PIN # confirmation is just one example. I used one of my common passwords expecting Schwab would treat it with the utmost care. To me, this would mean storing it in an encrypted, non-human readable form. Ideally, the password itself would not be stored at all. Instead, a hash of the password would be stored, and any time I entered my password, the hash of what I entered would be compared to the stored hash. This would protect my password from unscrupulous Schwab insiders, since statistics show that approximately 70% of security breaches occur from the inside. (read more…)

Two months ago, I had no idea who Hannah Montana was. My daughter is too young, thankfully, to care about Hannah and my nieces had not yet introduced me to the phenom. Now, she is my best friend. I love her! she rocks!

I should probably admit that I still really don’t have any idea who she is, and have never heard her music. The reason for my new found respect for Hannah is that two months ago, I changed my day job. I am now running technical operations for www.stubhub.com, a subsidiary of eBay.

If you’ve never heard of StubHub, click the banner on the left. StubHub is the leading secondary marketplace for concerts, sports events, and theater. If you want tickets to the World Series, the Super Bowl, or a sold-out concert, there is no better place than StubHub. And right now, Hannah Montana and Baseball Playoffs are the hot tickets.

People are going nuts for Hannah. As I write this, floor seats in Oakland, right in front of the stage are going for $1,500. There is also a luxury box with 20 tickets for over $11,000! This is the gotta have, must see, take me PLEEEAAASSSEEE!!!!! concert of the year. I love it!

I joined StubHub because it is truly my kind of company. First, it is a company with a solid foundation in the bricks-and-mortar world. People have been “scalping” tickets for a long time. By creating a neutral online marketplace, and backing it up with solid logistics and world class customer service, StubHub became the dominant player in the secondary ticket market. Second, it is a company that values its technology and its technologists. As such, it is a great place for an IT guy to work. Lastly, it is growing exponentially. The opportunity to design and build a highly-scalable, highly-available technical architecture was one I could not pass up.

Conceptually, I also love the free-market approach to ticket sales. StubHub does not take inventory of the tickets. We offer a secure place where fans can buy and sell tickets, and let the free market, not the ticket promoters set the market price. Hannah is a great example. The news is full of articles this week on parents complaining of being “gouged” by the ticket brokers. The Attorney General of Arkansas is investigating! What the people crying about the price seem to forget is the old laws of supply and demand. If they weren’t so desperate for the tickets, the price would fall.

I’ve neglected the blog lately, trying to get up to speed with the new gig. In the coming months, I have a bunch of articles planned based on the scalability challenges I am now facing. They should be worth the wait. In the mean time, visit StubHub, buy some tickets and go see Hannah. Let me know how you like the show.

PS> If you simply must see Hannah (in other words, you have a daughter), follow the StubHub advice for buying Hannah tickets. It may save you some money.

In part 1 of this series, I established the problem latency can cause in high speed networks. What one reader correctly referred to as “big long pipes.” To summarize, in large bandwidth networks that span long distances, network latency becomes the bottleneck that retards performance. The reason for this the impact of network delays on TCP windowing. In part, 2 I will discuss what to do about it.

Dealing with latency can be tricky business. The methods used to mitigate the impact of distance depends on many factors including the services being accessed, the protocols being used, and the amount of money you want to spend. What works for a home user does not work for a multi-national corporation. In general, there are 4 approaches one can take to deal with latency:

1. Tweak the host TCP settings
2. Change the protocol
3. Move the service closer to the user
4. Use a network accelerator

The first and least effective method is to tweak the TCP settings on your hosts. I say least effective for several reasons: It is hard to determine the correct TCP window size; not all operating systems support the RFC 1323 extensions; you may not have control of all the hosts; available bandwidth may change due to network congestion. Most importantly, some time sensitive applications such as VOIP will still exhibit problems in high latent networks, even if you tweak TCP. Still, if you are a home user on a big long pipe, this is the only option for you. Changing TCP is OS specific. Slaptijack.com has an excellent series on TCP tuning operating systems. Below are links to his specific guides as well as other sources: (read more…)

One concept that continues to elude many IT managers is the impact of latency on network design. 11 years ago, Stuart Cheshire wrote a detailed analysis on the difference between bandwidth and latency ISP links. Over a decade later, his writings are still relevant. Latency, not bandwidth, is often the key to network speed (or lack thereof).

I was reminded of Cheshire’s article and the underlying principles recently when working on an international WAN design. What Cheshire noted was that light signals pass through fibre optics at roughly 66% of the speed of light, or 200*10^6 m/s. Regardless of the equipment or protocols you use, your data cannot exceed that theoretical limit. This limit equals the delay between when a packet is sent, and when it is received, aka latency.

In the US, we tend to focus on bandwidth and carrier technology when ordering circuits, completely ignoring latency. For instance, when choosing between cable and DSL for your house do you ever ask the carrier for its latency SLA? Maybe you should. Using a cable connection a ping to www.google.com in Mountain View, CA from my house (137 KM) yields an average ping time (aka round-trip time or RTT) of 73ms. The theoretical latency for this distance (round trip) is 1.37ms meaning my cable connection is roughly 50 times worse than the theoretical limit. No surprise that Comcast focuses on bandwidth and not latency in its marketing. (read more…)

Recently, I was evaluating ISP’s for my hosting requirements. If you take a gander at 1-and-1, or most of the providers on the Personal Colocation site (and almost every other hosting provider in the world) they apportion your bandwidth in GB per month. Exactly what does this mean to people that are more familiar with buying bandwidth by the circuit? Exactly how much bandwidth is 500GB/Month? Is that equivalent to a T1 (DS1 or E1 for you euros?) (read more…)

Microsoft has released an updated daylight saving time fix for Windows Mobile. Nice of them to wait until 5 days before the change! I am recommending everyone use the official patch found here: http://www.microsoft.com/windowsmobile/daylightsaving/default.mspx, but I will leave my unoffical patch online.

I’m noticing a trend that many vendors are releasing last minute patches to fix DST issues with their 1st round of patches. If you have patched your systems already, I HIGHLY recommend you recheck with all your vendors to make sure they haven’t released an update. Good luck to all for this weekend.

-Bill

Amazon is now selling the BlackJack for FREE!!!CLICK HERE. Amazon changes its specials frequently, so I would not expect this deal to last. As we’ve discussed, this is a great phone.

With a 100% rebate, how can you lose? Order today.

As discussed here, the Daylight Saving Time change for 2007 is going to cause problems for unpatched technologies. Most vendors, including Microsoft, have released patches. One big area that is lacking is Windows Mobile smartphones & PDAs. Microsoft release a registry fix and instructed the carriers to push out a patch. Most of the carriers, in their infinite wisdom, have neglected to do so. If you rely on your Windows smartphone, you need this fix. Microsoft published the registry fix here. This fix requires you to build a CAB file and then install it. To save you the trouble, I have bundled the CAB file for you:

Microsoft Windows Mobile Daylight Saving Time Patch

You can either download the CAB file directly to your cell phone, or download to your PC, copy it via activesync to your phone, and then run it. (read more…)