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  • Exploring TCP throughput with DTrace

    - by user12820842
    One key measure to use when assessing TCP throughput is assessing the amount of unacknowledged data in the pipe. This is sometimes termed the Bandwidth Delay Product (BDP) (note that BDP is often used more generally as the product of the link capacity and the end-to-end delay). In DTrace terms, the amount of unacknowledged data in bytes for the connection is the different between the next sequence number to send and the lowest unacknoweldged sequence number (tcps_snxt - tcps_suna). According to the theory, when the number of unacknowledged bytes for the connection is less than the receive window of the peer, the path bandwidth is the limiting factor for throughput. In other words, if we can fill the pipe without the peer TCP complaining (by virtue of its window size reaching 0), we are purely bandwidth-limited. If the peer's receive window is too small however, the sending TCP has to wait for acknowledgements before it can send more data. In this case the round-trip time (RTT) limits throughput. In such cases the effective throughput limit is the window size divided by the RTT, e.g. if the window size is 64K and the RTT is 0.5sec, the throughput is 128K/s. So a neat way to visually determine if the receive window of clients may be too small should be to compare the distribution of BDP values for the server versus the client's advertised receive window. If the BDP distribution overlaps the send window distribution such that it is to the right (or lower down in DTrace since quantizations are displayed vertically), it indicates that the amount of unacknowledged data regularly exceeds the client's receive window, so that it is possible that the sender may have more data to send but is blocked by a zero-window on the client side. In the following example, we compare the distribution of BDP values to the receive window advertised by the receiver (10.175.96.92) for a large file download via http. # dtrace -s tcp_tput.d ^C BDP(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count -1 | 0 0 | 6 1 | 0 2 | 0 4 | 0 8 | 0 16 | 0 32 | 0 64 | 0 128 | 0 256 | 3 512 | 0 1024 | 0 2048 | 9 4096 | 14 8192 | 27 16384 | 67 32768 |@@ 1464 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 32396 131072 | 0 SWND(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count 16384 | 0 32768 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 17067 65536 | 0 Here we have a puzzle. We can see that the receiver's advertised window is in the 32768-65535 range, while the amount of unacknowledged data in the pipe is largely in the 65536-131071 range. What's going on here? Surely in a case like this we should see zero-window events, since the amount of data in the pipe regularly exceeds the window size of the receiver. We can see that we don't see any zero-window events since the SWND distribution displays no 0 values - it stays within the 32768-65535 range. The explanation is straightforward enough. TCP Window scaling is in operation for this connection - the Window Scale TCP option is used on connection setup to allow a connection to advertise (and have advertised to it) a window greater than 65536 bytes. In this case the scaling shift is 1, so this explains why the SWND values are clustered in the 32768-65535 range rather than the 65536-131071 range - the SWND value needs to be multiplied by two since the reciever is also scaling its window by a shift factor of 1. Here's the simple script that compares BDP and SWND distributions, fixed to take account of window scaling. #!/usr/sbin/dtrace -s #pragma D option quiet tcp:::send / (args[4]-tcp_flags & (TH_SYN|TH_RST|TH_FIN)) == 0 / { @bdp["BDP(bytes)", args[2]-ip_daddr, args[4]-tcp_sport] = quantize(args[3]-tcps_snxt - args[3]-tcps_suna); } tcp:::receive / (args[4]-tcp_flags & (TH_SYN|TH_RST|TH_FIN)) == 0 / { @swnd["SWND(bytes)", args[2]-ip_saddr, args[4]-tcp_dport] = quantize((args[4]-tcp_window)*(1 tcps_snd_ws)); } And here's the fixed output. # dtrace -s tcp_tput_scaled.d ^C BDP(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count -1 | 0 0 | 39 1 | 0 2 | 0 4 | 0 8 | 0 16 | 0 32 | 0 64 | 0 128 | 0 256 | 3 512 | 0 1024 | 0 2048 | 4 4096 | 9 8192 | 22 16384 | 37 32768 |@ 99 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 3858 131072 | 0 SWND(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count 512 | 0 1024 | 1 2048 | 0 4096 | 2 8192 | 4 16384 | 7 32768 | 14 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 1956 131072 | 0

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  • Antenna Aligner Part 4: Role'ing in the deep

    - by Chris George
    Since last time I've been trying to sort out the general workflow of the app. It's fundamentally not hard, there is a list of transmitters, you select a transmitter and it shows the compass view. Having done quite a bit of ajax/asp.net/html in the past, I immediately started off by creating two divs within my 'page', one for the list, one for the compass. Then using the onClick event in the list, this will switch the display attribute on the divs. This seemed to work, but did lead to some dodgy transitional redrawing artefacts which I was not happy with. So after some Googling I realised I was doing it all wrong! JQuery mobile has the concept of giving an object in html a data-role. By giving a div the attribute data-role="page" it is then treated as a separate page on the mobile device. Within the code, this is referenced like a html anchor in the form #mypage. Using this system, page transitions such as fade or slide are automatically applied which adds to the whole authenticity of the app! Here is a simple example: . <a href="#'compasspage">compass</a> . <div data-role="page" id="compasspage" data-add-back-btn="true"> But I don't want just a static link, I want to dynamically create my list, and get each list elements to switch to the compass page with the right information. So here is the jquery that I used to dynamically inject new <li> rows into the <ul> block. $('ul').append($('<li/>', {    //here appendin `<li>`     'data-role': "list-divider" }).append($('<a/>', {    //here appending `<a>` into `<li>`     'href': '#compasspage',     'data-transition': 'none',     'onclick': 'selectTx(' + i + ')',     'html': buttonHtml }))); $('ul').listview('refresh'); This is called within a for loop so the first 5 appropriate transmitters are used. There are several things of interest to note here. Firstly, I could not find a more elegant way to tell the target page which transmitter I've clicked on, so I have used the onclick event as well as the href attribute. The onclick event fires 'selectTx' which simply sets a global member variable to the specific index number I've clicked on. Yes it's not nice, but it works. Secondly, the data-transition attribute is set to 'none'. I wanted the transition between the pages to be a whooshy slidey effect. However this worked going to the compass page, but returning to the list page gave some undesirable visual artefacts (flickering, redrawing etc.). So I decided to remove the transitions all together, which was a shame. Thirdly, rather than embedding loads of html into the append command, I removed this out into a variable 'buttonHtml'. Doing this really tidied up my code. Until next time!

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  • Seamless STP with Oracle SOA Suite

    - by user12339860
    STP stands for “Straight Through Processing”. Wikipedia describes STP as a solution that enables “the entire trade process for capital markets and payment transactions to be conducted electronically without the need for re-keying or manual intervention, subject to legal and regulatory restrictions” .I will deal with the later part of the definition i.e “payment transactions without manual intervention” in this article. The STP that I am writing about involves the interaction between a Bank and its’ corporate customers,to that extent this business case is also called “Corporate Payments”.Simply put a  Corporate Payment-STP solution needs to connect the payment transaction right from the Corporate ERP into the Bank’s Payment Hub. A SOA based STP solution can do a lot more than just process transaction. But before I get to the solution let me describe the perspectives of the two primary parties in this interaction. The Corporate customer and the Bank. Corporate's Interaction with Bank:  Typically it is the treasury department of an enterprise which interacts with the Bank on a daily basis. Here is how a day of interaction would look like from the treasury department of a corp. Corporate Cash Retrieve Beginning of day totals Monitor Cash Accounts Send or receive cash between accounts Supply chain payments Payment Settlements Calculate settlement positions Retrieve End of Day totals Assess Transaction Financial Impact Short Term Investment Desk Retrieve Current Account information Conduct Investment activities Bank’s Interaction with the Corporate :  From the Bank’s perspective, the interaction starts from the point of on boarding a corporate customer to billing the corporate for the value added services it provides. Once the corporate is on-boarded the daily interaction involves Handle the various formats of data arriving from customers Process Beginning of Day & End of Day reporting request from customers Meet compliance requirements Process Payments Transmit Payment Status Challenges with this Interaction :  Both the Bank & the Corporate face many challenges from these interactions. Some of the challenges include Keeping a consistent view of transaction data for various LOBs of the corporate & the Bank Corporate customers use different ERPs, hence the data formats are bound to be different Can the Bank’s IT systems convert the data formats that can be easily mapped to the corporate ERP How does the Bank manage the communication profiles of these customers?  Corporate customers are demanding near real time visibility on their corporate accounts Corporate customers can make better cash management decisions if they can analyse the impact. Can the Bank create opportunities to sell its products to the investment desks at corporate houses & manage their orders? How will the Bank bill the corporate customer for the value added services it provides. What does a SOA based Seamless STP solution bring to the table? Highlights of Oracle SOA based STP solution For the Corporate Customer: No Manual or Paper based banking transactions Secure Delivery of Payment data to the Bank from multiple ERPs without customization Single Portal for monitoring & administering payment transactions Rule based validation of payments Customer has data necessary for more effective handling of payment and cash management decisions  Business measurements track progress toward payment cost goals  For the Bank: Reduces time & complexity of transactions Simplifies the process of introducing new products to corporate customers Single Payment hub for all corporate ERP payments across multiple instruments New Revenue sources by delivering value added services to customers Leverages existing payment infrastructure Remove Inconsistent data formats and interchange between bank and corporate systems  Compliance and many other benefits

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  • PowerShell: Read Excel to Create Inserts

    - by BuckWoody
    I’m writing a series of articles on how to migrate “departmental” data into SQL Server. I also hold workshops on the entire process – from discovering that the data exists to the modeling process and then how to design the Extract, Transform and Load (ETL) process. Finally I write about (and teach) a few methods on actually moving the data. One of those options is to use PowerShell. There are a lot of ways even with that choice, but the one I show is to read two columns from the spreadsheet and output statements that would insert the data using a stored procedure. Of course, you could re-write this as INSERT statements, out to a text file for bcp, or even use a database connection in the script to move the data directly from Excel into SQL Server. This snippet won’t run on your system, of course – it assumes a Microsoft Office Excel 2007 spreadsheet located at c:\temp called VendorList.xlsx. It looks for a tab in that spreadsheet called Vendors. The statement that does the writing just uses one column: Vendor Code. Here’s the breakdown of what I’m doing: In the first block, I connect to Microsoft Office Excel. That connection string is specific to Excel 2007, so if you need a different version you’ll need to look that up. In the second block I set up a selection from the entire spreadsheet based on that tab. Note that if you’re only after certain data you shouldn’t get the whole spreadsheet – that’s just good practice. In the next block I create the text I want, inserting the Vendor Code field as I go. Finally I close the connection. Enjoy! $ExcelConnection= New-Object -com "ADODB.Connection" $ExcelFile="c:\temp\VendorList.xlsx" $ExcelConnection.Open("Provider=Microsoft.ACE.OLEDB.12.0;` Data Source=$ExcelFile;Extended Properties=Excel 12.0;") $strQuery="Select * from [Vendors$]" $ExcelRecordSet=$ExcelConnection.Execute($strQuery) do { Write-Host "EXEC sp_InsertVendors '" $ExcelRecordSet.Fields.Item("Vendor Code").Value "'" $ExcelRecordSet.MoveNext()} Until ($ExcelRecordSet.EOF) $ExcelConnection.Close() Script Disclaimer, for people who need to be told this sort of thing: Never trust any script, including those that you find here, until you understand exactly what it does and how it will act on your systems. Always check the script on a test system or Virtual Machine, not a production system. All scripts on this site are performed by a professional stunt driver on a closed course. Your mileage may vary. Void where prohibited. Offer good for a limited time only. Keep out of reach of small children. Do not operate heavy machinery while using this script. If you experience blurry vision, indigestion or diarrhea during the operation of this script, see a physician immediately. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • How to securely delete files stored on a SSD?

    - by Chris Neuroth
    From a (very long, but definitely worth to read) article on SSDs: When you delete a file in your OS, there is no reaction from either a hard drive or SSD. It isn’t until you overwrite the sector (on a hard drive) or page (on a SSD) that you actually lose the data. File recovery programs use this property to their advantage and that’s how they help you recover deleted files. The key distinction between HDDs and SSDs however is what happens when you overwrite a file. While a HDD can simply write the new data to the same sector, a SSD will allocate a new (or previously used) page for the overwritten data. The page that contains the now invalid data will simply be marked as invalid and at some point it’ll get erased. So, what would be the best way to securely erase files stored on a SSD? Overwriting with random data as we are used to from hard disks (e.g. using the "shred" utility) won't work unless you overwrite the WHOLE drive...

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  • Architecture: Bringing Value to the Table

    - by Bob Rhubart
    A recent TechTarget article features an interview with Business Architecture expert William Ulrich (Take a business-driven approach to application modernization ). In that article Ulrich offers this advice: "Moving from one technical architecture might be perfectly viable on a project by project basis, but when you're looking at the big picture and you want to really understand how to drive business value so that the business is pushing money into IT instead of IT pulling money back, you have to understand the business architecture. When we do that we're going to really be able to start bringing value to the table." In many respects that big picture view is what software architecture is all about. As an architect, your technical skills must be top-notch. But if you don't apply that technical knowledge within the larger context of moving the business forward, what are you accomplishing? If you're interested in more insight from William Ulrich, you can listen to the ArchBeat Podcast interview he did last year, in which he and co-author Neal McWhorter talked about their book, Business Architecture: The Art and Practice of Business Transformation.

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  • Oracle Business Analytics bejelentés

    - by user645740
    Jelenleg is zajlik az Oracle Business Analytics bejelentés. Rövid regisztrációt követoen megnézhetjük az eloadásokat, késobb akár felvételrol is: http://www.oracle.com/us/corporate/events/business-analytics/index.html Klasszikusokkal szólva: "Mi már nem azok a lovagok vagyunk, akik azt mondják, hogy NI!" Mark Hurd és Balaji Yelamanchili világítja meg az Oracle stratégiáját a Business Analytics területen. Hogyan tudnak a döntéshozók eredményeebben és gyorsabban elemezni. Business Analytics, tervezett célrendszerek Exadata Database Machine, Big Data Appliance, Exalytics In-Memory Machine, teljesítménymenedzsment alkalmazások, az Endeca felvásárlás integrációja. A keynote utáni eloadások: Achieving Predictable Performance with Oracle Hyperion Enterprise Performance Management Explore All Relevant Data—Introducing Oracle Endeca Information Discovery Run Your Business Faster and Smarter with Oracle Business Intelligence Applications on Oracle Exalytics In-Memory Machine Analyzing and Deciding with Big Data http://www.oracle.com/us/corporate/events/business-analytics/index.html

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  • Upgarde from Asp.Net MVC 1 to MVC 2 - how to and issues with JsonRequestBehavior

    - by Renso
    Goal Upgrade your MVC 1 app to MVC 2 Issues You may get errors about your Json data being returned via a GET request violating security principles - we also address this here. This post is not intended to delve into why the Json GET request is or may be an issue, just how to resolve it as part of upgrading from MVC1 to 2. Solution First remove all references from your projects to the MVC 1 dll and replace it with the MVC 2 dll. Now update your web.config file in your web app root folder by simply changing references to assembly="System.Web.Mvc, Version 1.0.0.0 to Version 2.0.0.0, there are a couple of references in your config file, here are probably most of them you may have:         <compilation debug="true" defaultLanguage="c#">             <assemblies>                        <add assembly="System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />             </assemblies>         </compilation>           <pages masterPageFile="~/Views/Masters/CRMTemplate.master" pageParserFilterType="System.Web.Mvc.ViewTypeParserFilter, System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" pageBaseType="System.Web.Mvc.ViewPage, System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" userControlBaseType="System.Web.Mvc.ViewUserControl, System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" validateRequest="False">             <controls>                 <add assembly="System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" namespace="System.Web.Mvc" tagPrefix="mvc" />   Secondly, if you return Json objects from an ajax call via the GET method you ahve several options to fix this depending on your situation: 1. The simplest, as in my case I did this for an internal web app, you may simply do:             return Json(myObject, JsonRequestBehavior.AllowGet);   2. In Mvc if you have a controller base you could wrap the Json method with:         public new JsonResult Json(object data)         {             return Json(data, "application/json", JsonRequestBehavior.AllowGet);                    }   3. The most work would be to decorate your Actions with:         [AcceptVerbs(HttpVerbs.Get)]   4. Another tnat is also a lot of work that needs to be done to every ajax call returning Json is:                             msg = $.ajax({ url: $('#ajaxGetSampleUrl').val(), dataType: 'json', type: 'POST', async: false, data: { name: theClass }, success: function(data, result) { if (!result) alert('Failure to retrieve the Sample Data.'); } }).responseText;   This should cover all the issues you may run into when upgrading. Let me kow if you run into any other ones.

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  • Catching Up with Lisp

    Support for multicore and Big Data are among the upcoming features of Franz's Lisp-based tools Lisp - Programming - Languages - FAQs Help and Tutorials - Compilers and Interpreters

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  • dual boot missing files on ntfs

    - by yehuda
    I have 3 partitions: one for win7 (ntfs), one for Ubuntu (ext4) and one just for data (ntfs so both operating systems can see them). My problem is that I had stored some files on the data partition using ubuntu and when i booted win7 all that data was gone! After that I couldn't find the files even when using Ubuntu. My files were simply GONE :( Is there something I can do in Ubuntu or is it just windows problem?

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  • More Tables or More Databases?

    - by BuckWoody
    I got an e-mail from someone that has an interesting situation. He has 15,000 customers, and he asks if he should have a database for their data per customer. Without a LOT more data it’s impossible to say, of course, but there are some general concepts to keep in mind. Whenever you’re segmenting data, it’s all about boundary choices. You have not only boundaries around how big the data will get, but things like how many objects (tables, stored procedures and so on) that will be involved, if there are any cross-sections of data (do they share location or product information) and – very important – what are the security requirements? From the answer to these types of questions, you now have the choice of making multiple tables in a single database, or using multiple databases. A database carries some overhead – it needs a certain amount of memory for locking and so on. But it has a very clean boundary – everything from objects to security can be kept apart. Having multiple users in the same database is possible as well, using things like a Schema. But keeping 15,000 schemas can be challenging as well. My recommendation in complex situations like this is similar to a post on decisions that I did earlier – I lay out the choices on a spreadsheet in rows, and then my requirements at the top in the columns. I  give each choice a number based on how well it meets each requirement. At the end, the highest number wins. And many times it’s a mix – perhaps this person could segment customers into larger regions or districts or products, in a database. Within that database might be multiple schemas for the customers. Of course, he needs to query across all customers, that becomes another requirement. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • C# Tip - Rendering HTML in a Gridview cell

    - by BobPalmer
    Just a quick tip for working with the gridview in ASP.Net.  If your data column contains HTML text, you've probably seen something like this in your gridview after pulling the data: <font color="red">First Item</font><br/><font color="green">Second Item</font><br/><font color="blue">Third Item</font> To have the relevant column render in HTML, just go to your gridview property pages, find the column you need rendered in HTML, and click 'convert this Field into a TemplateField'.  The result is that as a template field, HTML within your bound data value will be rendered properly.  So our example above would transform into: First Item Second Item Third Item I primarily use this technique for enabling HTML content in comment fields, and to insert line breaks when building the data for these fields. Hope this helps out! -Bob

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  • Which one is better offline method for large scale application

    - by Manish Pansiniya
    We've a big data management website used by several property. Some of our customers have downtime (they can't access net for an hour or two). We want our site to support offline data viewing and inventory management (typical data search and add/remove) and when the user goes online we can sync the changes back to our central database. Customers use several platforms like Windows, iOS, etc. We've been looking into several different options, here are the major choices - Develop offline web app supported in HTML5. Develop a 'fallback' mechanism and interact with data from the app cache as explained in here (http://www.htmlgoodies.com/html5/tutorials/introduction-to-offline-web- applications-using-) Develop a desktop based cross platform solution. I remember the old MONO which has been popular. Here's a post (What do you suggest for cross platform apps, including web cross-platform-apps-including-web) and another one (Technology choice for cross platform development (desktop and phone)? platform-development-desktop-and-phone?rq=1) I realize the the desktop solution might be hard to maintain and result in some compatibility issues and demand test environments. Can HTML5 handle moderate to high level complexity and data flow? Or would it be better to rely on a desktop based app for better scalability & performance?

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  • Using the link command to keep backups on another drive

    - by Xavier
    I have a folder that contains a not so large amount of space called /data/backup. I have been told that if I link that folder (/data/backup) to an even bigger folder area like /bigdata/backup for example, that I will be able to execute backups to the /data/backup folder. It will then just create a link, but the data will be seen in both folders and the latter one (/bigdata/backup) will contain the backup results but it will show on both folders. Since the /bigdata/backup has far more disk space then the backup will no longer fail because of space problems in the /data/backup one. Is this true?

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  • New DataCenter Options for Windows Azure

    - by ScottKlein
    Effective immediately, new compute and storage resource options are now available when selecting data center options in the Windows Azure Portal. "West US" and "East US" options are now available, for Compute and Storage. SQL Azure options for these two data centers will be available in the next few months. The official announcement can be found here.In terms of geo-replication:US East and West are paired together for Windows Azure Storage geo-replicationUS North and South are paired together for Windows Azure Storage geo-replicationThese two new data centers are now visible in the Windows Azure Management Portal effective immediately. Compute and Storage pricing remains the same across all data centers. Get started with Windows Azure through the free 90 day trial.

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  • Why Wouldn't Root Be Able to Change a Zone's IP Address in Oracle Solaris 11?

    - by rickramsey
    You might assume that if you have root access to an Oracle Solaris zone, you'd be able to change the root's IP address. If so, you'd proceed along these lines ... First, you'd log in: root@global_zone:~# zlogin user-zone Then you'd remove the IP interface: root@user-zone:~# ipadm delete-ip vnic0 Next, you'd create a new IP interface: root@user-zone:~# ipadm create-ip vnic0 Then you'd assign the IP interface a new IP address (10.0.0.10): root@user-zone:~# ipadm create-addr -a local=10.0.0.10/24 vnic0/v4 ipadm: cannot create address: Permission denied Why would that happen? Here are some potential reasons: You're in the wrong zone Nobody bothered to tell you that you were fired last week. The sysadmin for the global zone (probably your ex-girlfriend) enabled link protection mode on the zone with this sweet little command: root@global_zone:~# dladm set-linkprop -p \ protection=mac-nospoof,restricted,ip-nospoof vnic0 How'd your ex-girlfriend learn to do that? By reading this article: Securing a Cloud-Based Data Center with Oracle Solaris 11 by Orgad Kimchi, Ron Larson, and Richard Friedman When you build a private cloud, you need to protect sensitive data not only while it's in storage, but also during transmission between servers and clients, and when it's being used by an application. When a project is completed, the cloud must securely delete sensitive data and make sure the original data is kept secure. These are just some of the many security precautions a sysadmin needs to take to secure data in a cloud infrastructure. Orgad, Ron, and Richard and explain the rest and show you how to employ the security features in Oracle Solaris 11 to protect your cloud infrastructure. Part 2 of a three-part article on cloud deployments that use the Oracle Solaris Remote Lab as a case study. About the Photograph That's the fence separating a small group of tourist cabins from a pasture in the small town of Tropic, Utah. Follow Rick on: Personal Blog | Personal Twitter | Oracle Forums   Follow OTN Garage on: Web | Facebook | Twitter | YouTube

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  • How many developers before continuous integration becomes effective for us?

    - by Carnotaurus
    There is an overhead associated with continuous integration, e.g., set up, re-training, awareness activities, stoppage to fix "bugs" that turn out to be data issues, enforced separation of concerns programming styles, etc. At what point does continuous integration pay for itself? EDIT: These were my findings The set-up was CruiseControl.Net with Nant, reading from VSS or TFS. Here are a few reasons for failure, which have nothing to do with the setup: Cost of investigation: The time spent investigating whether a red light is due a genuine logical inconsistency in the code, data quality, or another source such as an infrastructure problem (e.g., a network issue, a timeout reading from source control, third party server is down, etc., etc.) Political costs over infrastructure: I considered performing an "infrastructure" check for each method in the test run. I had no solution to the timeout except to replace the build server. Red tape got in the way and there was no server replacement. Cost of fixing unit tests: A red light due to a data quality issue could be an indicator of a badly written unit test. So, data dependent unit tests were re-written to reduce the likelihood of a red light due to bad data. In many cases, necessary data was inserted into the test environment to be able to accurately run its unit tests. It makes sense to say that by making the data more robust then the test becomes more robust if it is dependent on this data. Of course, this worked well! Cost of coverage, i.e., writing unit tests for already existing code: There was the problem of unit test coverage. There were thousands of methods that had no unit tests. So, a sizeable amount of man days would be needed to create those. As this would be too difficult to provide a business case, it was decided that unit tests would be used for any new public method going forward. Those that did not have a unit test were termed 'potentially infra red'. An intestesting point here is that static methods were a moot point in how it would be possible to uniquely determine how a specific static method had failed. Cost of bespoke releases: Nant scripts only go so far. They are not that useful for, say, CMS dependent builds for EPiServer, CMS, or any UI oriented database deployment. These are the types of issues that occured on the build server for hourly test runs and overnight QA builds. I entertain that these to be unnecessary as a build master can perform these tasks manually at the time of release, esp., with a one man band and a small build. So, single step builds have not justified use of CI in my experience. What about the more complex, multistep builds? These can be a pain to build, especially without a Nant script. So, even having created one, these were no more successful. The costs of fixing the red light issues outweighed the benefits. Eventually, developers lost interest and questioned the validity of the red light. Having given it a fair try, I believe that CI is expensive and there is a lot of working around the edges instead of just getting the job done. It's more cost effective to employ experienced developers who do not make a mess of large projects than introduce and maintain an alarm system. This is the case even if those developers leave. It doesn't matter if a good developer leaves because processes that he follows would ensure that he writes requirement specs, design specs, sticks to the coding guidelines, and comments his code so that it is readable. All this is reviewed. If this is not happening then his team leader is not doing his job, which should be picked up by his manager and so on. For CI to work, it is not enough to just write unit tests, attempt to maintain full coverage, and ensure a working infrastructure for sizable systems. The bottom line: One might question whether fixing as many bugs before release is even desirable from a business prespective. CI involves a lot of work to capture a handful of bugs that the customer could identify in UAT or the company could get paid for fixing as part of a client service agreement when the warranty period expires anyway.

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  • High Performance SQL Views Using WITH(NOLOCK)

    - by gt0084e1
    Every now and then you find a simple way to make everything much faster. We often find customers creating data warehouses or OLAP cubes even though they have a relatively small amount of data (a few gigs) compared to their server memory. If you have more server memory than the size of your database or working set, nearly any aggregate query should run in a second or less. In some situations there may be high traffic on from the transactional application and SQL server may wait for several other queries to run before giving you your results. The purpose of this is make sure you don’t get two versions of the truth. In an ATM system, you want to give the bank balance after the withdrawal, not before or you may get a very unhappy customer. So by default databases are rightly very conservative about this kind of thing. Unfortunately this split-second precision comes at a cost. The performance of the query may not be acceptable by today’s standards because the database has to maintain locks on the server. Fortunately, SQL Server gives you a simple way to ask for the current version of the data without the pending transactions. To better facilitate reporting, you can create a view that includes these directives. CREATE VIEW CategoriesAndProducts AS SELECT * FROM dbo.Categories WITH(NOLOCK) INNER JOIN dbo.Products WITH(NOLOCK) ON dbo.Categories.CategoryID = dbo.Products.CategoryID In some cases quires that are taking minutes end up taking seconds. Much easier than moving the data to a separate database and it’s still pretty much real time give or take a few milliseconds. You’ve been warned not to use this for bank balances though. More from Data Stream

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  • Spectacular Explosion On Sun [Video]

    - by Gopinath
    Yesterday seems to be it’s too hot inside the crust of Sun and it resulted in an big explosion!! An explosion that was spectacular to watch and the event was something like never seen before : a solar flare, a coronal wave, a filament eruption, a coronal mass ejection, coronal rain and a coronal mass ejection to name a few. Check the embedded video Did you notice the hole on the Sun when it exploded? It’s a really very big one and can accommodate many Earth’s into that (check this for size comparison) Image and story via Geeked On Goddard This article titled,Spectacular Explosion On Sun [Video], was originally published at Tech Dreams. Grab our rss feed or fan us on Facebook to get updates from us.

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  • Python response parse [migrated]

    - by Pavel Shevelyov
    When I'm sending some data on host: r = urllib2.Request(url, data = data, headers = headers) page = urllib2.urlopen(r) print page.read() I have something like this: [{"command":"settings","settings":{"basePath":"\/","ajaxPageState":{"theme":"spsr","theme_token":"kRHUhchUVpxAMYL8Y8IoyYIcX0cPrUstziAi8gSmMYk","css":[]},"ajax":{"edit-submit":{"callback":"spsr_calculator_form_ajax","wrapper":"calculator_form","method":"replaceWith","event":"mousedown","keypress":true,"url":"\/ru\/system\/ajax","submit":{"_triggering_element_name":"submit"}}}},"merge":true},{"command":"insert","method":null,"selector":null,"data":"\u003cdiv id=\"calculator_form\"\u003e\u003cform action=\"\/ru\/service\/calculator\" method=\"post\" id=\"spsr-calculator-form\" accept-charset=\"UTF-8\"\u003e\u003cdiv\u003e\u003cinput id=\"edit-from-ship-region-id\" type=\"hidden\" name=\"from_ship_region_id\" value=\"\" \/\u003e\n\u003cinput type=\"hidden\" name=\"form_build_id\" value=\"form-0RK_WFli4b2kUDTxpoqsGPp14B_0yf6Fz9x7UK-T3w8\" \/\u003e\n\u003cinput type=\"hidden\" name=\"form_id\" value=\"spsr_calculator_form\" \/\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"bg_p\"\u003e \n\u0421\u0435\u0439\u0447\u0430\u0441 \u0412\u044b... bla bla bla but I want have something, like this: <html><h1>bla bla bla</h1></html> How can I do it?

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