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  • Multi-petabyte scale out storage solution [closed]

    - by Alex Yuriev
    Let's say that I have a need to have a single-name space scale to multi-petabyte object store with a file system-like wrapper. What is currently out there that supports the following: Single name space that can take 1B files. Support for multiple entry points using NFS At least node level replication ( preferably node and file level replication ) Online software upgrades No "magic sauce" on the storage layer The following has been evaluated: Gluster & Lustre - just ick - fundamental lack of understanding of why online upgrades are mandatory. OneFS - we have it. It is smelling more and more like it hides a dead body under the hood. Other than MapR and zfs am I missing anything? P.S. Oh yes, I keep forgetting that the forums are for people to discuss if 2TB drive actually stores 2TB info. May bad. Seriously though - how the heck can "meets the following requirements" can be considered a "debate"? P.P.S. I did not throw an idiotic insult - i pointed out that this is actually an interesting question compared to a conversation about storage capacity of a 2TB hard drive. It is not a question of what works better - it is a question that asks did I miss any of the products that currently exist which fit the criteria where criteria is clearly outline. I got one answer below which included something that I have not looked at in a long time which looks quite a bit grown up compared to the time I briefly look at it before.

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  • what is best multi-server configuration with OpenVPN

    - by sebut
    We have a number of Database severs running MongoDB on Debian plus a number of Application servers also on Debian. The db servers hold replicating db clusters, so they need to talk to each other. Application servers need to talk to all db servers (for reasons of fault tolerance). The servers are potentially spread across multiple hosting centers, so we need secure channels between all servers. The number of servers is bound to grow, so we need a VPN solution that's easy to maintain and expand. This is why I feel that SSH that we use for testing might not be up to the task and OpenVPN seems the way to go. I have ruled out TAP, since I understand that this would mean all traffic going to all the servers - perhaps this is a misunderstanding and TAP acts more like a switch? With TUN devices I imagine that all DB servers would live in their own separate subnet, they would also need a client configured to be able to connect to each of their peers. The application servers could live in a common subnet range with a client config only. Does this sound like a reasonable setup? Strangely, on the web I did not find anything about multi-server with OpenVPN. Thanks for all insights and ideas!

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  • Reasons not to use MVC architecture for web application

    - by jaywon
    In the past I have primarily built all my web applications using an N-tier architecture, implementing the BLL and DAL layers. Recently, I have started doing some RoR development as well as looking into ASP.NET MVC. I understand the differences between the different architectures(as referenced by some other SO posts), but I can't really think of any reasons why I wouldn't choose an MVC model going forward. Is there any reasons/times in your experience when an MVC architecture would not be suitable, or any reasons why you would choose a BLL/DAL architecture instead?

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  • What goes between SQL Server and Client?

    - by worlds-apart89
    This question is an updated version of a previous question I have asked on here. I am new to client-server model with SQL Server as the relational database. I have read that public access to SQL Server is not secure. If direct access to the database is not a good practice, then what kind of layer should be placed between the server and the client? Note that I have a desktop application that will serve as the client and a remote SQL Server database that will provide data to the client. The client will input their username and password in order to see their data. I have heard of terms like VPN, ISA, TMG, Terminal Services, proxy server, and so on. I need a fast and secure n-tier architecture. P.S. I have heard of web services in front of the database. Can I use WCF to retrieve, update, insert data? Would it be a good approach in terms of security and performance?

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  • Implementing N-tire structure in .net

    - by pravakar
    Hi friends, my requirement is suppose i have three classes namely Employee, Customer and Department where Employee contains attributes i.e. id,name,dept and Customer class contains Id,name and Department class contains i.e. id and name. Now all these three class has common function i.e. create, update and delete. This functions i want to implement using interface. So can any one suugest me to perform these things in n-tier architecture.

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  • Does MVC replace traditional manually created BLL?

    - by used2could
    I'm used to creating the UI, BLL, DAL by hand (some times I've used LINQ-to-SQL or SubSonic for the DAL). I've done several small projects using MVC since its release. On these projects I've still continued to write a BLL and DAL by hand and then incorporate those into the MVC's models/controllers. I'm looking to optimize my time on projects this seems like overkill and a potential waste of time. Question Would it be acceptable to roll a DAL such as SubSonic and directly use it in the Models/Controllers of my MVC web app? Now the models & controllers would act as the BLL. I just see this as a major timesaver to not have to worry about another tier. UPDATE: I just wanted to add that my concern isn't really with the DAL (I frequently use SubSonic and NH) but rather focus on the BLL. Sorry for the confusion.

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  • Migrating Windows XP BOOT.INI Settings to Windows 7 Boot-loader

    - by Synetech inc.
    Two months ago my motherboard died, so I bought a used computer that came with Windows 7. I have since installed my old hard-drive, which had Windows XP on it, in this system. What I am trying to do now is to figure out a way to migrate the settings from XP's BOOT.INI into 7's boot-loader. Below is the BOOT.INI I used in XP (I have reduced the strings and updated the disks to point to the new location of the old HD. Oh and I am not clear on the drive letters. In XP, I could boot the recovery console or MS-DOS from a file in C:\ that contains the boot-sector. I am not sure what drive letter it would be called now—I had to manually change all the drive letters of the old partitions in Windows 7 because it auto-assigned them all wrong/differently). [boot loader] timeout=10 default=multi(0)disk(0)rdisk(1)partition(1)\WINDOWS [operating systems] multi(0)disk(0)rdisk(1)partition(1)\WINDOWS="XP" /fastdetect multi(0)disk(0)rdisk(1)partition(1)\WINDOWS="XP (Safe)" /safeboot:network /sos /bootlog /noguiboot C:\CMDCONS\BOOTSECT.DAT="Recovery Console" /cmdcons C:\BOOTSECT.DOS="MS-DOS 7.10" /win95 I have looked around, and have only been able to find some bcdedit commands to add XP to the boot-loader, but none that include information on setting safe-mode for it (or changing any of the XP load options for that matter). Not surprisingly I suppose, I have not found anything on adding the XP recovery console or DOS to the Windows 7 boot-loader. (Yes, I tried EasyBCD, but that did not help; it had no options for XP, and the best I managed was to get a choice of booting 7 or normal-mode XP—choosing XP didn't even give the old XP boot menu.) Can anyone please tell me how to export the entries in XP's boot.ini to 7's boot-loader so that on boot, I can choose to load the following: Windows 7 Windows 7 (Safe-mode) (Windows 7 (The Win7 counterpart of the Recovery Console)) Windows XP Windows XP (Safe-mode) Windows XP (Recovery Console) MS-DOS 7.10

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  • Migrating Windows XP BOOT.INI Settings to Windows 7 Boot-loader

    - by Synetech inc.
    Hi, Two months ago my motherboard died, so I bought a used computer that came with Windows 7. I have since installed my old hard-drive, which had Windows XP on it, in this system. What I am trying to do now is to figure out a way to migrate the settings from XP's BOOT.INI into 7's boot-loader. Below is the BOOT.INI I used in XP (I have reduced the strings and updated the disks to point to the new location of the old HD. Oh and I am not clear on the drive letters. In XP, I could boot the recovery console or MS-DOS from a file in C:\ that contains the boot-sector. I am not sure what drive letter it would be called now—I had to manually change all the drive letters of the old partitions in Windows 7 because it auto-assigned them all wrong/differently). [boot loader] timeout=10 default=multi(0)disk(0)rdisk(1)partition(1)\WINDOWS [operating systems] multi(0)disk(0)rdisk(1)partition(1)\WINDOWS="XP" /fastdetect multi(0)disk(0)rdisk(1)partition(1)\WINDOWS="XP (Safe)" /safeboot:network /sos /bootlog /noguiboot C:\CMDCONS\BOOTSECT.DAT="Recovery Console" /cmdcons C:\BOOTSECT.DOS="MS-DOS 7.10" /win95 I have looked around, and have only been able to find some bcdedit commands to add XP to the boot-loader, but none that include information on setting safe-mode for it (or changing any of the XP load options for that matter). Not surprisingly I suppose, I have not found anything on adding the XP recovery console or DOS to the Windows 7 boot-loader. (Yes, I tried EasyBCD, but that did not help; it had no options for XP, and the best I managed was to get a choice of booting 7 or normal-mode XP—choosing XP didn't even give the old XP boot menu.) Can anyone please tell me how to export the entries in XP's boot.ini to 7's boot-loader so that on boot, I can choose to load the following: Windows 7 Windows 7 (Safe-mode) (Windows 7 (The Win7 counterpart of the Recovery Console)) Windows XP Windows XP (Safe-mode) Windows XP (Recovery Console) MS-DOS 7.10

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  • Ubuntu 10.04 LTS - Dual monitor works only sometimes (ATI multi-desktop)

    - by Beres Botond
    I've been using my laptop with an external LCD monitor attached to it at work (Philips 201E). And at home with a different external monitor (Samsung 2032BW). I have an ATI graphics card (HD3450), with Ati Catalyst drivers enabled and I'm using the Single display desktop (Multi-Desktop) seeting. At work I have the external monitor on the left and laptop on the right, while at home the other way around. So when I switch between the two setups, I just needed to go to Ati Catalyst Control Center, change the order of the displays, change the resolution (Home - 1680x1050, Work - 1440x900), reboot and it was all fine. But since a while it doesn't work properly anymore: At home it still works fine. At work it doesn't work. Sometimes it works for some reason, after a few resolution/setting changes in ACCC and reboots... it's very strange and annoying. With the home monitor I can see the whole bootup process on both monitors (laptop + LCD) and it always just works fine. With the work monitor on the external LCD monitor I just see "No video input" until I get to the login screen, then it shows up there as well. But after login it will either: Flicker a few times, but then work OK. Or (more often) Flicker once and then go back to "No video input" again. I usually end up rebooting a few times until it works. Does anyone have any idea for fixing it? This is my xorg.conf currently: Section "ServerLayout" Identifier "amdcccle Layout" Screen 0 "amdcccle-Screen[6]-0" 0 0 Screen "amdcccle-Screen[6]-1" 1280 0 EndSection Section "Files" EndSection Section "Module" Load "glx" EndSection Section "ServerFlags" Option "Xinerama" "off" EndSection Section "Monitor" Identifier "0-LVDS" Option "VendorName" "ATI Proprietary Driver" Option "ModelName" "Generic Autodetecting Monitor" Option "DPMS" "true" Option "PreferredMode" "1280x768" Option "TargetRefresh" "60" Option "Position" "0 0" Option "Rotate" "normal" Option "Disable" "false" EndSection Section "Monitor" Identifier "0-CRT1" Option "VendorName" "ATI Proprietary Driver" Option "ModelName" "Generic Autodetecting Monitor" Option "DPMS" "true" Option "TargetRefresh" "60" Option "Position" "0 0" Option "Rotate" "normal" Option "Disable" "false" Option "PreferredMode" "1440x900" EndSection Section "Device" Identifier "Default Device" Driver "fglrx" EndSection Section "Device" Identifier "amdcccle-Device[6]-0" Driver "fglrx" Option "Monitor-LVDS" "0-LVDS" BusID "PCI:6:0:0" EndSection Section "Device" Identifier "amdcccle-Device[6]-1" Driver "fglrx" Option "Monitor-CRT1" "0-CRT1" BusID "PCI:6:0:0" Screen 1 EndSection Section "Screen" Identifier "Default Screen" DefaultDepth 24 SubSection "Display" Virtual 2560 1024 EndSubSection EndSection Section "Screen" Identifier "amdcccle-Screen[6]-0" Device "amdcccle-Device[6]-0" DefaultDepth 24 SubSection "Display" Viewport 0 0 Depth 24 EndSubSection EndSection Section "Screen" Identifier "amdcccle-Screen[6]-1" Device "amdcccle-Device[6]-1" DefaultDepth 24 SubSection "Display" Viewport 0 0 Depth 24 EndSubSection EndSection

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  • node.js on multi-core machines

    - by zaharpopov
    node.js looks interesting BUT... I must miss something - isn't node.js tuned only to run on a single process & thread? Then how does it scale for multi-core CPUs and multi-CPU servers? After all, it is all great to make fast as possible single-thread server, but for high loads I would want to use several CPUs. And the same goes for making applications faster - seems today the way is use multiple CPUs and parallelize the tasks. How does node.js fit into this picture? Is its idea to somehow distribute multiple instances or what?

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  • Rhino Mocks, Dependency Injection, and Separation of Concerns

    - by whatispunk
    I am new to mocking and dependency injection and need some guidance. My application is using a typical N-Tier architecture where the BLL references the DAL, and the UI references the BLL but not the DAL. Pretty straight forward. Lets say, for example, I have the following classes: class MyDataAccess : IMyDataAccess {} class MyBusinessLogic {} Each exists in a separate assembly. I want to mock MyDataAccess in the tests for MyBusinessLogic. So I added a constructor to the MyBusinessLogic class to take an IMyDataAccess parameter for the dependency injection. But now when I try to create an instance of MyBusinessLogic on the UI layer it requires a reference to the DAL. I thought I could define a default constructor on MyBusinessLogic to set a default IMyDataAccess implementation, but not only does this seem like a codesmell it didn't actually solve the problem. I'd still have a public constructor with IMyDataAccess in the signature. So the UI layer still requires a reference to the DAL in order to compile. One possible solution I am toying with is to create an internal constructor for MyBusinessLogic with the IMyDataAccess parameter. Then I can use an Accessor from the test project to call the constructor. But there's still that smell. What is the common solution here. I must just be doing something wrong. How could I improve the architecture?

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  • Create multi-part message in MIME format Freemarker template

    - by Mat Banik
    How do you create email message that contains text and HTML version for the same content? Of course I would like to know how to setup the freemarker template or the header of the message that will be send. When I look on the source of message multi-part message in MIME format that I receive in inbox every once in while this is what is in there: This is a multi-part message in MIME format. ------=_NextPart_000_B10D_01CBAAA8.F29DB300 Content-Type: text/plain Content-Transfer-Encoding: 7bit ...Text here... ------=_NextPart_000_B10D_01CBAAA8.F29DB300 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <html><body> html code here ... </body></html>

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  • SQL Server CLR stored procedures in data processing tasks - good or evil?

    - by Gart
    In short - is it a good design solution to implement most of the business logic in CLR stored procedures? I have read much about them recently but I can't figure out when they should be used, what are the best practices, are they good enough or not. For example, my business application needs to parse a large fixed-length text file, extract some numbers from each line in the file, according to these numbers apply some complex business rules (involving regex matching, pattern matching against data from many tables in the database and such), and as a result of this calculation update records in the database. There is also a GUI for the user to select the file, view the results, etc. This application seems to be a good candidate to implement the classic 3-tier architecture: the Data Layer, the Logic Layer, and the GUI layer. The Data Layer would access the database The Logic Layer would run as a WCF service and implement the business rules, interacting with the Data Layer The GUI Layer would be a means of communication between the Logic Layer and the User. Now, thinking of this design, I can see that most of the business rules may be implemented in a SQL CLR and stored in SQL Server. I might store all my raw data in the database, run the processing there, and get the results. I see some advantages and disadvantages of this solution: Pros: The business logic runs close to the data, meaning less network traffic. Process all data at once, possibly utilizing parallelizm and optimal execution plan. Cons: Scattering of the business logic: some part is here, some part is there. Questionable design solution, may encounter unknown problems. Difficult to implement a progress indicator for the processing task. I would like to hear all your opinions about SQL CLR. Does anybody use it in production? Are there any problems with such design? Is it a good thing?

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  • .NET Membership with Repository Pattern

    - by Zac
    My team is in the process of designing a domain model which will hide various different data sources behind a unified repository abstraction. One of the main drivers for this approach is the very high probability that these data sources will undergo significant change in the near future and we don't want to be re-writing business logic when this happens. One data source will be our membership database which was originally implemented using the default ASP.Net Membership Provider. The membership provider is tied to the System.Web.Security namespace but we have a design guideline requiring that our domain model layer is not dependent upon System.Web (or any other implementation/environment dependency) as it will be consumed in different environments - nor do we want our websites directly communicating with databases. I am considering what would be a good approach to reconciling the MembershipProvider approach with our abstracted n-tier architecture. My initial feeling is that we could create a "DomainMembershipProvider" which interacts with the domain model and then implement objects in the model which deal with the repository and handle validation/business logic. The repository would then implement data access using our (as-yet undecided) ORM/data access tool. Are there are any glaring holes in this approach - I haven't worked closely with the MembershipProvider class so may well be missing something. Alternatively, is there an approach that you think will better serve the requirements I described above? Thanks in advance for your thoughts and advice. Regards, Zac

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  • Question on multi-probe Local Sensitive Hashing

    - by Yijinsei
    Hey guys sorry to be asking this kind noob question, but because I really need some guidance on how to use Multi probe LSH pretty urgently, so I did not do much research myself. I realize there is a lib call LSHKIT available that implemented that algorithm, but I have trouble trying to figure out how to use it. Right now, I have a few thousand feature vector 296 dimension, each representing an image. The vector is used to query an user input image, to retrieve the most similar image. The method I used to derive the distance between vector is euclidean distance. I know this might be a rather noob question, but do you guys have knowledge on how should i implement multi probe LSH? I am really very grateful to any answer or response.

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  • Multi-part gzip file random access (in Java)

    - by toluju
    This may fall in the realm of "not really feasible" or "not really worth the effort" but here goes. I'm trying to randomly access records stored inside a multi-part gzip file. Specifically, the files I'm interested in are compressed Heretrix Arc files. (In case you aren't familiar with multi-part gzip files, the gzip spec allows multiple gzip streams to be concatenated in a single gzip file. They do not share any dictionary information, it is simple binary appending.) I'm thinking it should be possible to do this by seeking to a certain offset within the file, then scan for the gzip magic header bytes (i.e. 0x1f8b, as per the RFC), and attempt to read the gzip stream from the following bytes. The problem with this approach is that those same bytes can appear inside the actual data as well, so seeking for those bytes can lead to an invalid position to start reading a gzip stream from. Is there a better way to handle random access, given that the record offsets aren't known a priori?

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  • Screening (multi)collinearity in a regression model

    - by aL3xa
    I hope that this one is not going to be "ask-and-answer" question... here goes: (multi)collinearity refers to extremely high correlations between predictors in the regression model. How to cure them... well, sometimes you don't need to "cure" collinearity, since it doesn't affect regression model itself, but interpretation of an effect of individual predictors. One way to spot collinearity is to put each predictor as a dependent variable, and other predictors as independent variables, determine R2, and if it's larger than .9 (or .95), we can consider predictor redundant. This is one "method"... what about other approaches? Some of them are time consuming, like excluding predictors from model and watching for b-coefficient changes - they should be noticeably different. Of course, we must always bare in mind specific context/goal of analysis... Sometimes, only remedy is to repeat a research, but right now, I'm interested in various ways of screening redundant predictors when (multi)collinearity occurs in a regression model.

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  • Screening (multi)collinearity in a reggresion model

    - by aL3xa
    I hope that this one is not going to be "ask-and-answer" question... here goes: (multi)collinearity refers to extremely high correlations between predictors in the regression model. How to cure them... well, sometimes you don't need to "cure" collinearity, since it doesn't affect regression model itself, but interpretation of an effect of individual predictors. One way to spot collinearity is to put each predictor as a dependent variable, and other predictors as independent variables, determine R2, and if it's larger than .9 (or .95), we can consider predictor redundant. This is one "method"... what about other approaches? Some of them are time consuming, like excluding predictors from model and watching for b-coefficient changes - they should be noticeably different. Of course, we must always bare in mind specific context/goal of analysis... Sometimes, only remedy is to repeat a research, but right now, I'm interested in various ways of screening redundant predictors when (multi)collinearity occurs in a regression model.

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  • Multi-tab application (C#)

    - by Zach
    Hi, I'm creating a multi-tabbed .NET application that allows the user to dynamically add and remove tabs at runtime. When a new tab is added, a control is added to it (as a child), in which the contents can be edited (eg. a text box). The user can perform tasks on the currently visible text box using a toolbar/menu bar. To better explain this, look at the picture below to see an example of what I want to accomplish. It's just a mock-up, so it doesn't actually work that way, but it shows what I want to get done. Essentially, like a multi-tabbed Notepad. View the image here: http://picasion.com/pic15/324b466729e42a74b9632c1473355d3b.gif Is this possible in .NET? I'm pretty sure it is, I'm just looking for a way that it can be implemented.

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  • Is it possible to use multi keyboards with multi keyboard layouts simultaneously?

    - by mono
    Considering to switch to dvorak layout, but this terminal is used by multi users as the same user account. It is unacceptable to ask all people to switch layout, plus it is hard to use dvorak layout with a keyboard qwerty-ly labeled. But there are spare (USB,qwerty) keyboards, so if I plug another keyboard in and be able to use multi layouts on different psyical keyboard simultaneously (I will rearrange letters on keys), the problem get solved. solution for either windows or linux is fine. anyway thanks all.

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  • Using Maven shade plugin in a multi module project

    - by Manoj
    I have a scenario where-in I need to create an uber jar of a multi module maven project including all modules and their dependencies. I tried using maven shade plugin. but it seems to work only when I use it at the module level. If I add the plugin entry in parent pom then the build breaks (it tries to shade the parent pom) [INFO] Replacing original artifact with shaded artifact. [INFO] Replacing null with C:\Projects\foo.bar\target\foobar-0.0.1-SNAPSHOT-shaded.pom [INFO] ------------------------------------------------------------------------ [ERROR] BUILD ERROR [INFO] ------------------------------------------------------------------------ [INFO] Error creating shaded jar: null It does seem to make sense since the <packaging> for the parent maven project is pom. But there should be some way to create an uber jar for a multi module project... Any ideas people???

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  • Multi-Threaded Application - Help with some pseudo code!!

    - by HonorGod
    I am working on a multi-threaded application and need help with some pseudo-code. To make it simpler for implementation I will try to explain that in simple terms / test case. Here is the scenario - I have an array list of strings (say 100 strings) I have a Reader Class that reads the strings and passes them to a Writer Class that prints the strings to the console. Right now this runs in a Single Thread Model. I wanted to make this multi-threaded but with the following features - Ability to set MAX_READERS Ability to set MAX_WRITERS Ability to set BATCH_SIZE So basically the code should instantiate those many Readers and Writers and do the work in parallel. Any pseudo code will really be helpful to keep me going!

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