What happens when it rains?

Amazon S3 and data corruption. Thread: S3 data corruption?

We've isolated this issue to a single load balancer that was brought into service at 10:55pm PDT on Friday, 6/20.  It was taken out of service at 11am PDT Sunday, 6/22.  While it was in service it handled a small fraction of Amazon S3's total requests in the US.  Intermittently, under load, it was corrupting single bytes in the byte stream.  When the requests reached Amazon S3, if the Content-MD5 header was specified, Amazon S3 returned an error indicating the object did not match the MD5 supplied.  When no MD5 is specified, we are unable to determine if transmission errors occurred, and Amazon S3 must assume that the object has been correctly transmitted. Based on our investigation with both internal and external customers, the small amount of traffic received by this particular load balancer, and the intermittent nature of the above issue on this one load balancer, this appears to have impacted a very small portion of PUTs during this time frame.
One of the things we'll do is improve our logging of requests with MD5s, so that we can look for anomalies in their 400 error rates.  Doing this will allow us to provide more proactive notification on potential transmission issues in the future, for customers who use MD5s and those who do not. In addition to taking the actions noted above, we encourage all of our customers to take advantage of mechanisms designed to protect their applications from incorrect data transmission.  For all PUT requests, Amazon S3 computes its own MD5, stores it with the object, and then returns the computed MD5 as part of the PUT response code in the ETag.  By validating the ETag returned in the response, customers can verify that Amazon S3 received the correct bytes even if the Content MD5 header wasn't specified in the PUT request.  Because network transmission errors can occur at any point between the customer and Amazon S3, we recommend that all customers use the Content-MD5 header and/or validate the ETag returned on a PUT request to ensure that the object was correctly transmitted.  This is a best practice that we'll emphasize more heavily in our documentation to help customers build applications that can handle this situation.
If you have specific questions or concerns about how your application might have been affected, please feel free to e-mail us at aws@amazon.com.

When I used the 3.0 Firefox installer I have a version that reports 2.0.0.14  that's messed up.

I have been working on moving a lot of inline styles to a separate CSS page today.  There are some asp:datagrid that I would like to control paging(number of pages, page mode…) and other settings in one configuration location rather then each page.  I just realized I was looking for MVC.

CBS has placed some of its classic TV shows such as Star Trek, Hawaii Five-O, MacGyver online for our viewing pleasure.

Microsoft gave us a new toy to play with to help us scale better.

“Velocity” is a distributed in-memory application cache platform for developing scalable, available, and high-performance applications. Using “Velocity,” applications can store any serializable CLR object without concern for where the object gets stored because data is cached across multiple computers. “Velocity” allows copies of data to be stored across the cache cluster, protecting data against failures. It can be configured to run as a service accessed over the network or can be run embedded with the distributed application. “Velocity” includes an ASP.NET session provider object enabling storage of ASP.NET session objects in the distributed cache without having to write to databases, which increases the performance and scalability of ASP.NET applications.

Down load the CTP

Project Velocity’s team blog

brief demo of WCF using Twitter’s REST API Programming Twitter with WCF 3.5

by Dariusz.

You can now run a sysinternal tool off any computer just by visiting http://live.sysinternals.com/ pretty cool.  For more details on the sysinternal tools check out http://technet.microsoft.com/sysinternals.

In the bay area there have been a couple well noted ATM scams lately Lunardi and Arco.  We should all take note ATM systems are not safe.

Could you tell the above ATM has a card reader?  Read the full article at ATM Scam.  Or ATM Skimming

Perhaps it's time to start entering our banks again.

It seems that we developers have a new hobby Arm Chair Architecture, and this time poor Twitter seems to be our target.

Jeff started with Twitter: Service vs. Platform,

Followed by Dare's  Some Thoughts on Twitter's Availability Problems,

And then.. Robert Should Services Charge Super Users.

Finally all this noise  provoked the definitive source to opine on the issue Twittering About Architecture

This reminds me of our little Fizsbusz issues of the past.  Many developers ready to offer solutions for problems they don't fully understand.  Remember it's computer science.  If your first response isn't a question your doing it wrong.

ps its great to see Dare blogging again!

Moody's Investor Service, which already has egg on its face for all those great ratings it gave to subprime-backed mortgage bonds, has a new problem to deal with. It reported that a computer coding error may have led to some debt products receiving a higher rating than they should have received.broker universe

That is going to be a hard mistake to live down.  How much fault would you say that kind of error was for our current liquidly crisis?