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From: Cliff Lloyd

Sent: Tuesday, February 9. 2016 7:44 PM

TO: Candice McQueen; Ashley M. Ball; Stephen M. Smith; Nakia Towns; Jayme Place; Sara
Gast; Kathleen Airhart; Vicki Kirk; Tammy L. Shelton

Subject: RE: {Please Review Tonight: Paper and Pencil FAQ

Why the MIST Platform Failed on Monday

The MIST platform is powered by multiple servers that reside inside a commercial data center. The MIST servers are
interconnected via a local wired network, which also connects the MIST servers to the Internet.

At around 8:25 CST a sequence of events saturated the capacity of the local wired network. Once saturated the local
network was no longer able to transmit data between the Internet and the servers. The consequence of this was that
students attempting to connect to the MIST platform from the Internet were denied access making it impossible to
execute the assessment.

The sequence of events that resulted in excessive network M) are believed to be abnormal cache activity, compounded
by the cepying of large ?les between servers, database backup activity and the execution of an SQL Query used to
provide activity summaries against a key transaction data table. As connection errors began to occur, the system
attempted to log these errors further adding to network traf?c and in essence creating a self propagating denial of service
event.

MIST server capacity, volume of users at the time of failure and district infrastructure did not contribute to this event. It
appears that greater procedural and operational rigor could have prevented the network outage.

Cliff Lloyd Chief Information Officer

TN Dept. of Education

Andrew Johnson Tower, 9th Floor

710 James Robertson Parkway, Nashville, TN 37243

(615) 626-0020
movieducati on

From: Candice McQueen
Sent: Tuesday, February 09, 2016 6:08 PM
To: Cliff Lloyd; Ashley M. Ball; Stephen M. Smith; Nakia Towns; Jayme Place; Sara Gast; Kathleen Airhart; Vicki Kirk;

Tammy L. Shelton
Subject: Re: <Please Review Tonight> Paper and Pencil FAQ

Cliff,

Can you send the more detailed version of the answer as it might be helpful? We can then determine if we use
it or stick with what we have.

Candice

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Candice McQueen, Commissioner

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