|By Gary Kaiser||
|July 14, 2014 08:45 AM EDT||
In Part IV, we wrapped up our discussions on bandwidth, congestion and packet loss. In Part V, we examine the four types of processing delays visible on the network, using the request/reply paradigm we outlined in Part I.
Server Processing (Between Flows)
From the network's perspective, we allocate the time period between the end of a request flow and the beginning of the corresponding reply flow to server processing. Generally speaking, the server doesn't begin processing a request until it has received the entire flow, i.e., the last packet in the request message; similarly, the server doesn't begin sending the reply until it has finished processing the request. We sometimes refer to these delays between flows as "pure" processing delays, distinct from another type of intra-flow processing delay we call starved for data and discuss later. Server processing delays occur as a result of a request message, and therefore always occur within a thread.
Transaction Trace Illustrations
These "pure" server processing delays are generally relatively simple to detect, to understand, and to prove. Transaction Trace's Node Processing table lists all of the observed processing delays for an operation in tabular format; by splitting this table with the Bounce Diagram and highlighting a row of interest, the Bounce Diagram will display the last packet of the request flow and the first packet of the corresponding reply flow, effectively diagramming the measurement.
Use the Node Processing Table split with the Bounce Diagram to illustrate node processing delay
You may also use the Thread Analysis split with the Bounce Diagram; this will provide a view of the request and reply packet flows as well as the processing measurement.
Split the Thread View with the Bounce Diagram to illustrate the request flow, node processing and reply flow
Starved for Data (Sending Node, Within a Flow)
Sometimes, the network interface will be able to transmit data at a rate faster than the sending application can deliver to the TCP socket. For example, a busy ftp server may momentarily interrupt sending a large file because of a disk, memory or CPU bottleneck. We refer to these pauses that occur in the middle of a flow as "starved for data" conditions; there is nothing on the network (no TCP flow control constraint) preventing the request or reply flow from continuing, so the cause must be internal to the sending node. Starved for data bottlenecks occur within a flow (instead of between flows), and are related to the sending node - either the client or server.
Transaction Trace Illustration
These cases can be more difficult to visualize. Since the condition is generally not too common, it is often best to rule out other performance bottlenecks first, before checking for data starvation. When it does occur, the condition has the effect of extending the duration of a request or reply flow, and starved for data delays are included in Transaction Trace's Node Sending measurements. Sort the rate column of the Node Sending Table and split the window with the Bounce Diagram; the Bounce Diagram will illustrate the packets associated with a sending measurement. For those sending measurements where you suspect a starved for data condition, look for idle periods of time where the sending node's flow has been interrupted. Importantly, a starved for data delay will terminate with the transmission of a data packet that resumes the sender's flow, not a TCP ACK from the receiver that might suggest a TCP or application window constraint.
The Node Sending table is split with the Bounce Diagram to help illustrate Starved for Data conditions; note the pause in transmission that resumes independent of any TCP ACK.
Client Processing (Between Flows)
From the network's perspective, we allocate the time period between the end of a reply flow and the beginning of the next request flow to client processing. Generally speaking, the client cannot begin processing a reply until it has received the entire reply flow, i.e., the last packet of the reply message; similarly, the client doesn't begin sending the next (new) request until it has completed processing the reply. (This correlation generally applies to request/reply flows on the same TCP connection.)
Transaction Trace Illustrations
Similar to server processing delays, client delays are relatively simple to understand. In most cases, client delays occur between threads; in other words, after one thread has completed but before the next thread begins. For tasks with thread-level decodes, Transaction Trace's Thread Analysis Gantt chart view can illustrate these delays well.
Gaps between threads are associated with client processing delays
Discounting Client Processing
Note that we assume strict adherence to the definition of "operation" here; click to screen update. If the trace has captured multiple steps - say the user navigates through a series of operations - then the user "think time" between steps will appear as client processing delay, with corresponding gaps between threads. You may still use these multi-step tasks for analysis, remembering to discount client processing delays. Alternatively, you can save each step as a separate task by selecting a sequence of threads from the Thread table.
For more network strategies, click here for the full article.
The definition of IoT is not new, in fact it’s been around for over a decade. What has changed is the public's awareness that the technology we use on a daily basis has caught up on the vision of an always on, always connected world. If you look into the details of what comprises the IoT, you’ll see that it includes everything from cloud computing, Big Data analytics, “Things,” Web communication, applications, network, storage, etc. It is essentially including everything connected online from ha...
Nov. 22, 2014 10:00 PM EST Reads: 1,015
We are all here because we are sold on the transformative promise of The Cloud. But what good is all of this ephemeral, on-demand infrastructure if your usage doesn't actually improve the agility and speed of your business? How must Operations adapt in order to avoid stifling your Cloud initiative? In his session at DevOps Summit, Damon Edwards, co-founder and managing partner of the DTO Solutions, will highlight the successful organizational, process, and tooling patterns of high-performing c...
Nov. 22, 2014 08:45 PM EST Reads: 917
Software-driven innovation is becoming a primary approach to how businesses create and deliver new value to customers. A survey of 400 business and IT executives by the IBM Institute for Business Value showed businesses that are more effective at software delivery are also more profitable than their peers nearly 70 percent of the time (1). DevOps provides a way for businesses to remain competitive, applying lean and agile principles to software development to speed the delivery of software that ...
Nov. 22, 2014 08:00 PM EST Reads: 1,425
Docker offers a new, lightweight approach to application portability. Applications are shipped using a common container format and managed with a high-level API. Their processes run within isolated namespaces that abstract the operating environment independently of the distribution, versions, network setup, and other details of this environment. This "containerization" has often been nicknamed "the new virtualization." But containers are more than lightweight virtual machines. Beyond their small...
Nov. 22, 2014 06:45 PM EST Reads: 1,121
The move in recent years to cloud computing services and architectures has added significant pace to the application development and deployment environment. When enterprise IT can spin up large computing instances in just minutes, developers can also design and deploy in small time frames that were unimaginable a few years ago. The consequent move toward lean, agile, and fast development leads to the need for the development and operations sides to work very closely together. Thus, DevOps become...
Nov. 22, 2014 05:45 PM EST Reads: 1,216
Cloud Expo 2014 TV commercials will feature @ThingsExpo, which was launched in June, 2014 at New York City's Javits Center as the largest 'Internet of Things' event in the world.
Nov. 22, 2014 05:30 PM EST Reads: 1,265
An entirely new security model is needed for the Internet of Things, or is it? Can we save some old and tested controls for this new and different environment? In his session at @ThingsExpo, New York's at the Javits Center, Davi Ottenheimer, EMC Senior Director of Trust, reviewed hands-on lessons with IoT devices and reveal a new risk balance you might not expect. Davi Ottenheimer, EMC Senior Director of Trust, has more than nineteen years' experience managing global security operations and asse...
Nov. 22, 2014 05:30 PM EST Reads: 1,053
The major cloud platforms defy a simple, side-by-side analysis. Each of the major IaaS public-cloud platforms offers their own unique strengths and functionality. Options for on-site private cloud are diverse as well, and must be designed and deployed while taking existing legacy architecture and infrastructure into account. Then the reality is that most enterprises are embarking on a hybrid cloud strategy and programs. In this Power Panel at 15th Cloud Expo (http://www.CloudComputingExpo.com...
Nov. 22, 2014 07:00 AM EST Reads: 1,334
Explosive growth in connected devices. Enormous amounts of data for collection and analysis. Critical use of data for split-second decision making and actionable information. All three are factors in making the Internet of Things a reality. Yet, any one factor would have an IT organization pondering its infrastructure strategy. How should your organization enhance its IT framework to enable an Internet of Things implementation? In his session at Internet of @ThingsExpo, James Kirkland, Chief Ar...
Nov. 21, 2014 09:15 PM EST Reads: 1,256
Leysin American School is an exclusive, private boarding school located in Leysin, Switzerland. Leysin selected an OpenStack-powered, private cloud as a service to manage multiple applications and provide development environments for students across the institution. Seeking to meet rigid data sovereignty and data integrity requirements while offering flexible, on-demand cloud resources to users, Leysin identified OpenStack as the clear choice to round out the school's cloud strategy. Additional...
Nov. 21, 2014 08:45 PM EST Reads: 1,215
The security devil is always in the details of the attack: the ones you've endured, the ones you prepare yourself to fend off, and the ones that, you fear, will catch you completely unaware and defenseless. The Internet of Things (IoT) is nothing if not an endless proliferation of details. It's the vision of a world in which continuous Internet connectivity and addressability is embedded into a growing range of human artifacts, into the natural world, and even into our smartphones, appliances, a...
Nov. 21, 2014 08:00 PM EST Reads: 1,272
Technology is enabling a new approach to collecting and using data. This approach, commonly referred to as the "Internet of Things" (IoT), enables businesses to use real-time data from all sorts of things including machines, devices and sensors to make better decisions, improve customer service, and lower the risk in the creation of new revenue opportunities. In his General Session at Internet of @ThingsExpo, Dave Wagstaff, Vice President and Chief Architect at BSQUARE Corporation, discuss the ...
Nov. 21, 2014 08:00 PM EST Reads: 1,334
"BSQUARE is in the business of selling software solutions for smart connected devices. It's obvious that IoT has moved from being a technology to being a fundamental part of business, and in the last 18 months people have said let's figure out how to do it and let's put some focus on it, " explained Dave Wagstaff, VP & Chief Architect, at BSQUARE Corporation, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Nov. 21, 2014 07:00 PM EST Reads: 1,213
The 4th International DevOps Summit, co-located with16th International Cloud Expo – being held June 9-11, 2015, at the Javits Center in New York City, NY – announces that its Call for Papers is now open. Born out of proven success in agile development, cloud computing, and process automation, DevOps is a macro trend you cannot afford to miss. From showcase success stories from early adopters and web-scale businesses, DevOps is expanding to organizations of all sizes, including the world's large...
Nov. 21, 2014 06:45 PM EST Reads: 1,178
Verizon Enterprise Solutions is simplifying the cloud-purchasing experience for its clients, with the launch of Verizon Cloud Marketplace, a key foundational component of the company's robust ecosystem of enterprise-class technologies. The online storefront will initially feature pre-built cloud-based services from AppDynamics, Hitachi Data Systems, Juniper Networks, PfSense and Tervela. Available globally to enterprises using Verizon Cloud, Verizon Cloud Marketplace provides a one-stop shop fo...
Nov. 21, 2014 05:30 PM EST Reads: 1,140
"Our premise is Docker is not enough. That's not a bad thing - we actually love Docker. At ActiveState all our products are based on open source technology and Docker is an up-and-coming piece of open source technology," explained Bart Copeland, President & CEO of ActiveState Software, in this SYS-CON.tv interview at DevOps Summit at Cloud Expo®, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Nov. 20, 2014 10:30 PM EST Reads: 1,274
DevOps Summit 2015 New York, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - announces that it is now accepting Keynote Proposals. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete...
Nov. 20, 2014 09:00 PM EST Reads: 1,465
Infor has announced a new feature Infor CloudSuite™ Aerospace & Defense (A&D) to aid compliance with International Traffic in Arms Regulations (ITAR). The ITAR function will serve as a complementary function for new or existing Infor CloudSuite A&D customers, to facilitate compliance for Infor customers that are creating a US defense article or performing a US defense service and wish to benefit from cloud-services. The ITAR regulation serves to manage handling and access requirements for dat...
Nov. 20, 2014 07:00 PM EST Reads: 1,284
What do a firewall and a fortress have in common? They are no longer strong enough to protect the valuables housed inside. Like the walls of an old fortress, the cracks in the firewall are allowing the bad guys to slip in - unannounced and unnoticed. By the time these thieves get in, the damage is already done and the network is already compromised. Intellectual property is easily slipped out the back door leaving no trace of forced entry. If we want to reign in on these cybercriminals, it's hig...
Nov. 20, 2014 07:00 PM EST Reads: 1,157