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• Calculating IOPS for a single HDD - what am I doing wrong?

  - by red888

  So I know there is no standardized way of calculating IOPS for a HDD, but from everything I have read it appears one of the most accurate formulas is the following: IOP/ms = + {rotational latency} + ({block size} / {data transfer rate}) Which is IOs per millisecond or what the book I've been reading calls "Disk Service Time". Also rotational latency is calculated as half of one rotation in milliseconds. This was taken from the EMC book "Information Storage and Management" -arguably a pretty reliable source right\wrong? Putting this formula into practice consider this Seagate data sheet. I am going to calculate IOPS for the ST3000DM001 model for a block size of 4kb: Seek Average (Write) = 9.5 -I'll measuring IOPS for writes Spindle speed = 7200rpm Average Data Rate = 156MB/s So my variables are: Seek Time = 9.5ms Rotational latency = (.5 / (7200rpm / 60)) = 0.004s = 4ms Data Rate = 156MB/s = (0.156MB/ms / 0.004MB) = 39 9.5ms + 4ms + 39 = IO/ms 52.5 1 / (52.5 * 0.001) = 19 IOPS 19 IOPS for this drive clearly is not right so what am I doing wrong?

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• Dynamically removing records when certain columns = 0; data cleansing

  - by cdburgess

  I have a simple card table: CREATE TABLE `users_individual_cards` ( `id` int(11) NOT NULL AUTO_INCREMENT, `user_id` char(36) NOT NULL, `individual_card_id` int(11) NOT NULL, `own` int(10) unsigned NOT NULL, `want` int(10) unsigned NOT NULL, `trade` int(10) unsigned NOT NULL, PRIMARY KEY (`id`), UNIQUE KEY `user_id` (`user_id`,`individual_card_id`), KEY `user_id_2` (`user_id`), KEY `individual_card_id` (`individual_card_id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=1; I have ajax to add and remove the records based on OWN, WANT, and TRADE. However, if the user removes all of the OWN, WANT, and TRADE cards, they go to zero but it will leave the record in the database. I would prefer to have the record removed. Is checking after each "update" to see if all the columns = 0 the only way to do this? Or can I set a conditional trigger with something like: //psuedo sql AFTER update IF (OWN = 0, WANT = 0, TRADE = 0) DELETE What is the best way to do this? Can you help with the syntax?

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• How to implement a lazy loaded Silverlight data grid without using paging

  - by Marc Wittke

  Using the Business Application template from the brand new released RIA Services, you can see lots of examples using the data grid on top of a DomainDataSource in combination with a DataPager. The properties PageSize and LoadSize can be used to adjust the amount of data to be displayed in one page and the data that is prefetched in the background. Now I'd like to have a data grid with a scrollbar and no pager. The underlying DomainDataSource should load only the data that is diplayed in the grid. It should trigger another load, when the user scrolls down to items that are not yet in the data context. Is there any sample implementation how to do this?

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• NHibernate and SetSessionAuth audit columns

  - by user86431

  We have audit columns set by triggers. For obscure security reasons predating my tenure and out of my control, we log in with a generic user, and do a 'set session authorization' to change the user to the db user of the user who is logged in. When we converted to NHibernate, it creates a whole new session and jacks everything up when we try to do a set session auth, so we turned the set session auth off... Now we are trying to find out a way to get NHibernate to let us do 'set session authorization' without recycling the session on us, so we can use our existing trigger based audit column stuff with both legacy apps, and our new NHibernate apps. It's not a ideal soloution, or the best way to do it even, but is it possible? I was hoping there was a alternate interface that allowed this kind of access. Does anyone know how to do it, or can you point me towards and good hints? Thanks, Eric-

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• Does private browsing prevent socket events?

  - by Chris Cirefice

  I usually do my work in Google Chrome (v36.0.1985.143), private browsing enabled. I use Firefox to browse Stack Exchange, in normal mode so that all my logins are persisted. Sometimes I accidentally open an SE question in Chrome, so I copy-paste the URL to Firefox and get on reading. I left the SE tab in Chrome open, and up-voted a question in Firefox. Normally, you immediately see other users' voting activity via socket event emitting (possibly Socket.IO, I don't know SE's back-end). I noticed that in my Chrome tab, I didn't see the upvote that I had cast in Firefox. I had to refresh to be able to see the vote count change. So, as the title of the question states: does private browsing prevent socket events?

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• Receive and Process Email with ASP.NET / C# [closed]

  - by Arthur Chaparyan

  Possible Duplicates: Recommendations for a .NET component to access an email inbox coding for how to receive a mail in windows apllication What methods are there for having .NET code run and handle e-mails as they arrive? I'm developing a social networking site that will allow users to send an email to an email address that is for posting. This is the same thing Blogger does. This allows me to take a picture with my phone and send it to [email protected] and have it posted to my profile. The site is running IIS6 and I have full access to the server. Emails are currently being processed using the SMTP service that comes with Windows 2003 Server, but I can switch to another system without any issues. I am assuming I would have to somehow have the incoming emails either go into a folder that my application is watching or cause incoming emails to trigger a script. can anyone point me in the right direction?

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• Can I use manifests to specify an optional dependency on a COM server?

  - by sharptooth

  I'd like to use manifests to specify a dependency on a COM server (reg-free COM). The consumer application will mostly work fine without the COM server - only something like 1,7% of its functionality uses the COM server. So with plain old regsvr32 it would start and work fine until the user would do something that would trigger CoCreateInstance() call and at that point the consumer would get an error message. Now I've played with manifests for a while and it looks like the consumer wouldn't even start unless the COM server assembly it depends on is present in the file system. That's no good. Is there a way to use reg-free COM with manifests and make the dependency optional - so that the consumer program starts and works fine until CoCreateInstance() is actually called?

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• Returned JSON is seemingly mixed up when using jQuery Ajax

  - by Niall Paterson

  I've a php script that has the following line: echo json_encode(array('success'=>'true','userid'=>$userid, 'data' => $array)); It returns the following: { "success": "true", "userid": "1", "data": [ { "id": "1", "name": "Trigger", "image": "", "subtitle": "", "description": "", "range1": null, "range2": null, "range3": null }, { "id": "2", "name": "DWS", "image": "", "subtitle": "", "description": "", "range1": null, "range2": null, "range3": null } ] } But when I call a jQuery ajax as below: $.ajax({ type: 'POST', url: 'url', crossDomain: true, data: {name: name}, success: function(success, userid, data) { if (success = true) { document.write(userid); document.write(success); } } }); The userid is 'success'. The actual success one works, its true. Is this malformed data being returned? Or is it simply my code? Thanks in advance, Niall

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• Wpf Listbox and CheckBox

  - by Tan

  Hi iam using a listbox to show a list of items. in the listbox i ahve an togglebutton on every item. When i click on the toggle button the state of the togglebutton is pressed. But when i am scrolling down in the listbox and scolls up again. The togglebutton state is not pressed. How can i prevent this please help. Heres my itemtemplate <ListBox.ItemTemplate> <DataTemplate> <StackPanel Margin="0,3,0,0"> <Border BorderBrush="Black" BorderThickness="1,1,1,1"> <Border.Background> <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0" MappingMode="RelativeToBoundingBox"> <GradientStop Color="#FFECECEC" Offset="1"/> <GradientStop Color="#FFE8E8E8"/> <GradientStop Color="#FFBDBDBD" Offset="0.153"/> <GradientStop Color="#FFE8E8E8" Offset="0.904"/> </LinearGradientBrush> </Border.Background> <Border.Style> <Style> <Style.Triggers> <DataTrigger Binding="{Binding Path=IsSelected, RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type ListBoxItem}}}" Value="True"> <Setter Property="Border.Height" Value="100"/> <Setter Property="Border.Background"> <Setter.Value> <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0" MappingMode="RelativeToBoundingBox"> <GradientStop Color="DarkGray" Offset="1"/> <GradientStop Color="#FFE8E8E8"/> <GradientStop Color="#FFBDBDBD" Offset="0.153"/> <GradientStop Color="DarkGray" Offset="0.904"/> </LinearGradientBrush> </Setter.Value> </Setter> </DataTrigger> </Style.Triggers> </Style> </Border.Style> <StackPanel Orientation="Horizontal" VerticalAlignment="Center"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="500"/> <ColumnDefinition Width="100"/> <ColumnDefinition Width="55"/> </Grid.ColumnDefinitions> <!--Pick number--> <StackPanel Grid.Column="0" VerticalAlignment="Center" Orientation="Vertical"> <TextBlock Text="{Binding Path=FtgNamn}" FontWeight="Bold" FontSize="22pt" FontFamily="Calibri"/> <TextBlock Text="{Binding Path=LevsAttBeskr}" FontSize="18pt" FontFamily="Calibri"/> </StackPanel> <!--Pick Quantity--> <StackPanel Grid.Column="1" VerticalAlignment="Center"> <TextBlock Text="{Binding Path=Antal}" FontSize="44pt" FontFamily="Calibri"/> </StackPanel> <!-- Checkbox--> <StackPanel Grid.Column="2" VerticalAlignment="Center" HorizontalAlignment="Center"> <ToggleButton Name="Check" Width="40" Height="40" Click="Check_Click" Tag="{Binding Path=Plocklista}"> <ToggleButton.Style> <Style TargetType="ToggleButton"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type ToggleButton}"> <Border x:Name="InnerBorder" Background="White" BorderBrush="Black" BorderThickness="1"/> <ControlTemplate.Triggers> <Trigger Property="IsChecked" Value="True"> <Setter TargetName="InnerBorder" Property="Background"> <Setter.Value> <ImageBrush ImageSource="/Images/button_ok.png"/> </Setter.Value> </Setter> <Setter TargetName="InnerBorder" Property="BorderThickness" Value="0"/> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Setter.Value> </Setter> </Style> </ToggleButton.Style> </ToggleButton> </StackPanel> </Grid> <Border BorderBrush="Darkgray" BorderThickness="0,0,1,0"> </Border> <TextBlock Width="100" Text="{Binding Path=Quantity}" FontSize="44pt" FontFamily="Calibri"/> <CheckBox Width="78"/> </StackPanel> </Border> </StackPanel> </DataTemplate>

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• WPF MVVM Property Change Animation

  - by cjibo

  I am looking for a clean way to start an animation that will have dynamic values. Basically I want to do an animation where an element changes width based on the data of another element. Say I have a TextBlock that's Text Property is Binding. When this property changes I want a visual element say a Rectangle for our sake to do a DoubleAnimation changing the width from previous value to the new value. I am trying to stay away from putting code in my view if possible. I've looked into DataTriggers but they seem to require that you know what the value would be such as an Enum. In my case it is just the value changing that needs to trigger a storyboard and the animation would need to start at the current(previous) value and move nicely to the new value. Any ideas. Maybe I just missed a property.

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• How to implement Auto_Increment per User, on the same table?

  - by Jonas

  I would like to have multiple users that share the same tables in the database, but have one auto_increment value per user. I will use an embedded database, JavaDB and as what I know it doesn't support this functionality. How can I implement it? Should I implement a trigger on inserts that lookup the users last inserted row, and then add one, or are there any better alternative? Or is it better to implement this in the application code? Or is this just a bad idea? I think this is easier to maintain than creating new tables for every user. Example: table +----+-------------+---------+------+ | ID | ID_PER_USER | USER_ID | DATA | +----+-------------+---------+------+ | 1 | 1 | 2 | 3454 | | 2 | 2 | 2 | 6567 | | 3 | 1 | 3 | 6788 | | 4 | 3 | 2 | 1133 | | 5 | 4 | 2 | 4534 | | 6 | 2 | 3 | 4366 | | 7 | 3 | 3 | 7887 | +----+-------------+---------+------+ SELECT * FROM table WHERE USER_ID = 3 +----+-------------+---------+------+ | ID | ID_PER_USER | USER_ID | DATA | +----+-------------+---------+------+ | 3 | 1 | 3 | 6788 | | 6 | 2 | 3 | 4366 | | 7 | 3 | 3 | 7887 | +----+-------------+---------+------+ SELECT * FROM table WHERE USER_ID = 2 +----+-------------+---------+------+ | ID | ID_PER_USER | USER_ID | DATA | +----+-------------+---------+------+ | 1 | 1 | 2 | 3454 | | 2 | 2 | 2 | 6567 | | 4 | 3 | 2 | 1133 | | 5 | 4 | 2 | 4534 | +----+-------------+---------+------+

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• hibernate formula with column

  - by coolguy

  I have a table with a column that will be encrypted by a trigger after the record is inserted. When I read the column, I need to apply a decrypt function in the hibernate domain class. While saving the object, the value of the column will be saved as such. While reading the column, apply a database function on the read data. @Formula and @Column annotation cannot be applied to an attribute in the entity class. How do I achieve this functionality without using one attribute for saving and another one with @Formula for reading it?

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• django: how to interconnect various logical pieces of a webpage

  - by facha

  Hi, everyone. I'm just starting with django, so sorry for a possibly stupid question. Imagine, I have a webpage with 3 logical pieces: content, dynamic menu, banners. It seems ok to me to have a template with something like: {% include "banners.html" %} {% include "menu.html" %} {% include "content.html" %} But then, how do I do it? Every piece has its separate logic in a separate view in its' separate app. How do I trigger execution of all three views and render all three templates? P.S. Is there a sourceforge-like site for django apps where I could take a look at how people are doing stuff in real projects?

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• MS-DOS 7.1, Active-Boot

  - by user3005255

  I created a MS-DOS 7.1 (Win 98) active-boot USB-flash stick and it functions properly. Nevertheless I still have some unsolved issues: I want to change my keyboard-layout to german but I don´t know where to start since I only have the "basic-DOS" with IO.sys, MSDOS.sys + command.com. I already created Autoexec.bat + config.sys but don´t know which files I need and which I have to change in order to get a german keyboard. Also I can´t really shutdown my DOS properly, what is the right way to do it in MS-DOS 7.1? Thanks very much in advance for your help!

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• How to stop an Android Service ONLY when there are no other activities in my app running?

  - by johnrock

  Is there a way I can test if there are any other activities in my app still alive? I am looking to stop a service in an onDestroy method, but only want to do this if there are no other activities from my app still alive on the stack. I have the call stop the service in the main activity's onDestroy() method. This works perfect EXCEPT that if a user launches my app, then launches a few activities in my app, then hits the home screen and RELAUNCHES my app, they will subvert my order and the main activity will now be above other activities of my app. From this state, if they hit the back button and 'back out' of my home screen they will trigger the onDestroy() method and kill the service even though there are other activities open on the stack. I want to avoid this by stopping the service ONLY if I am sure there are no other activities of mine open on the stack. Possible?

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• How to deal with 'bad' decision forced on you regarding basic software for your product

  - by raticulin

  Here is my situation, our product used to support several of the major databases. Now management has decided to move all products to MaxDB (aka SapDB previously), and even if we keep supporting some of the previous dbs, all new installations are on MaxDB. I am sure MaxDB is a great db and can support huge SAP installations. But from the point of view of a software developper, its a nightmare. Every time you need to do something not trivial (write an stored procedure, some fancy trigger...) and you google for some info, you get like 0.1% of the hits you would with things like MySql, PostgreSql or MSSql. Mailing lists are nearly non existant. SAP does support it commercially but it is not clear wether we'll buy support. And the decision cannot be rolled back. The product works with MaxDB, but with lots of inefficiency on development and a lot of frustration, is there something one could do?

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• Having Troubles Getting My Apache Server Online(NodeJS and Apache)

  - by Jeff Armingol

  I am new here. This is my situation. I am using nodejs modules, serialport2 and socket.io, because I am trying to forward the data from my arduino hardware through serialports. In my server side script, I read the data then forward it to the client side. Now I am using Apache to serve the html page,which is the client side. I am running Nodejs on port 8000 and Apache on port 80. It is running OKAY when I view it in my browser typing localhost:80. The data is appearing and seems fine. Now when I tried to get my Apache server online using a Free DDNS provider(http://www.noip.com/) and my port80, it loaded the webpage but there are no data appearing on the page. What seems to be the problem here? Really need your expertise and advice. Thanks in advanced!

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• C# Processing Enter Key on Custom Container

  - by tycobb

  I am currently building a custom container control. Everything was going along smoothly until I hit a snag during testing. I noticed that the Enter key is not getting processed to the control that has focus inside the container. Everything else works as expected though. I am able to click the button with either the mouse or space bar, but enter does not want to get processed. After doing endless searches on container controls and processing the enter key I have come up with no solution. I tried returning Enter as true in IsInputKey(Keys keyData) and that didn't work. Neither did setting KeyPreview on the form. I have tried it with my custom button and .NET's standard button. Like I mentioned earlier, spacebar will trigger the desired effect. Please tell me what I am missing. There has to be an easy / stupid simple way to get Enter to process over to the active child control.

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• Can I pop up alert in javascript using php.

  - by Shantanu Gupta

  I want to trigger javascript alert using PHP. Is it possible I want to use it in head section, for displaying it at load time. <head> <?php $valid="valid"; if(!isset($valid)) echo "<script type=\"text/javascript\"> alert('Hi');</script>"; ?> </head> EDIT i want to display javascript alert() at load time after checking existance of session

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• When and why will an OS initialise memory to 0xCD, 0xDD, etc. on malloc/free/new/delete?

  - by LeopardSkinPillBoxHat

  I know that the OS will sometimes initialise memory with certain patterns such as 0xCD and 0xDD. What I want to know is when and why this happens. When Is this specific to the compiler used? Do malloc/new and free/delete work in the same way with regard to this? Is it platform specific? Will it occur on other operating systems, such as Linux or VxWorks? Why My understanding is this only occurs in Win32 debug configuration, and it is used to detect memory overruns and to help the compiler catch exceptions. Can you give any practical examples as to how this initialisation is useful? I remember reading something (maybe in Code Complete 2) that it is good to initialise memory to a known pattern when allocating it, and certain patterns will trigger interrupts in Win32 which will result in exceptions showing in the debugger. How portable is this?

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• Perl MiniWebserver

  - by snikolov

  hey guys i have config this miniwebserver, however i require the server to download a file in the local directory i am getting a problem can you please fix my issue thanks !/usr/bin/perl use strict; use Socket; use IO::Socket; my $buffer; my $file; my $length; my $output; Simple web server in Perl Serves out .html files, echos form data sub parse_form { my $data = $_[0]; my %data; foreach (split /&/, $data) { my ($key, $val) = split /=/; $val =~ s/+/ /g; $val =~ s/%(..)/chr(hex($1))/eg; $data{$key} = $val;} return %data; } Setup and create socket my $port = shift; defined($port) or die "Usage: $0 portno\n"; my $DOCUMENT_ROOT = $ENV{'HOME'} . "public"; my $server = new IO::Socket::INET(Proto = 'tcp', LocalPort = $port, Listen = SOMAXCONN, Reuse = 1); $server or die "Unable to create server socket: $!" ; Await requests and handle them as they arrive while (my $client = $server-accept()) { $client-autoflush(1); my %request = (); my %data; { -------- Read Request --------------- local $/ = Socket::CRLF; while (<$client>) { chomp; # Main http request if (/\s*(\w+)\s*([^\s]+)\s*HTTP\/(\d.\d)/) { $request{METHOD} = uc $1; $request{URL} = $2; $request{HTTP_VERSION} = $3; } # Standard headers elsif (/:/) { (my $type, my $val) = split /:/, $_, 2; $type =~ s/^\s+//; foreach ($type, $val) { s/^\s+//; s/\s+$//; } $request{lc $type} = $val; } # POST data elsif (/^$/) { read($client, $request{CONTENT}, $request{'content-length'}) if defined $request{'content-length'}; last; } } } -------- SORT OUT METHOD --------------- if ($request{METHOD} eq 'GET') { if ($request{URL} =~ /(.*)\?(.*)/) { $request{URL} = $1; $request{CONTENT} = $2; %data = parse_form($request{CONTENT}); } else { %data = (); } $data{"_method"} = "GET"; } elsif ($request{METHOD} eq 'POST') { %data = parse_form($request{CONTENT}); $data{"_method"} = "POST"; } else { $data{"_method"} = "ERROR"; } ------- Serve file ---------------------- my $localfile = $DOCUMENT_ROOT.$request{URL}; Send Response if (open(FILE, "<$localfile")) { print $client "HTTP/1.0 200 OK", Socket::CRLF; print $client "Content-type: text/html", Socket::CRLF; print $client Socket::CRLF; my $buffer; while (read(FILE, $buffer, 4096)) { print $client $buffer; } $data{"_status"} = "200"; } else { $file = 'a.pl'; open(INFILE, $file); while (<INFILE>) { $output .= $_; ##output of the file } $length = length($output); print $client "'HTTP/1.0 200 OK", Socket::CRLF; print $client "Content-type: application/octet-stream", Socket::CRLF; print $client "Content-Length:".$length, Socket::CRLF; print $client "Accept-Ranges: bytes", Socket::CRLF; print $client 'Content-Disposition: attachment; filename="test.zip"', Socket::CRLF; print $client $output, Socket::CRLF; print $client 'Content-Transfer-Encoding: binary"', Socket::CRLF; print $client "Connection: Keep-Alive", Socket::CRLF; # #$data{"_status"} = "404"; # } close(FILE); Log Request print ($DOCUMENT_ROOT.$request{URL},"\n"); foreach (keys(%data)) { print (" $_ = $data{$_}\n"); } ----------- Close Connection and loop ------------------ close $client; } END

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• eclipse: calling organizeimports programmatcally

  - by Stefan Roka

  Hi, I'm trying to execute 'OrganizeImports' programmatically on files that I'm editing programmatically. My code looks like this: final ICommandService cmdService = (ICommandService)PlatformUI.getWorkbench().getService (ICommandService.class); if (cmdService != null) { final Command cmd = cmdService.getCommand(IJavaEditorActionDefinitionIds.ORGANIZE_IMPORTS); final ExecutionEvent execEvt = new ExecutionEvent(cmd, Collections.EMPTY_MAP, compileationUnit, null); PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage(); ResourcesPlugin.getWorkspace(). Display.getDefault().syncExec(new Runnable() { @Override public void run() { try { //cmd.executeWithChecks(execEvt); cmd.execute(execEvt); } catch (Exception e) { getLogger().severe("organize imports failed: " + e.getMessage()); } } My problem is that OrganizeImportsAction executes on the current selection which is not the same as the compilation unit I'm editing. I would like to set the selection programmatically on the compilation unit but I don't know how to do that. Or maybe there is another way to trigger OrganizeImports. thanks, stefan

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• When to override OnError?

  - by Ek0nomik

  I'm looking into re-working and simplifying our error handling in an application I support. We currently have all of our pages inheriting from a base class we created, which in turn obviously inherits from System.Web.UI.Page. Within this base class, the OnError method is currently being overridden, and in turn calling MyBase.OnError, and then calling one of our custom logging methods. I don't see any benefit of overriding the OnError method, and I think it would be better to let the Application_Error method in the Global.asax take care of the unhandled exception (logging it) and then the customErrors section in the config would trigger a process to redirect the user. Looking online it looks like people override this method quite frequently, but I don't see a need to and this article from MSDN makes me think the same.

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• How can a single disk in a hardware SATA RAID-10 array bring the entire array to a screeching halt?

  - by Stu Thompson

  Prelude: I'm a code-monkey that's increasingly taken on SysAdmin duties for my small company. My code is our product, and increasingly we provide the same app as SaaS. About 18 months ago I moved our servers from a premium hosting centric vendor to a barebones rack pusher in a tier IV data center. (Literally across the street.) This ment doing much more ourselves--things like networking, storage and monitoring. As part the big move, to replace our leased direct attached storage from the hosting company, I built a 9TB two-node NAS based on SuperMicro chassises, 3ware RAID cards, Ubuntu 10.04, two dozen SATA disks, DRBD and . It's all lovingly documented in three blog posts: Building up & testing a new 9TB SATA RAID10 NFSv4 NAS: Part I, Part II and Part III. We also setup a Cacit monitoring system. Recently we've been adding more and more data points, like SMART values. I could not have done all this without the awesome boffins at ServerFault. It's been a fun and educational experience. My boss is happy (we saved bucket loads of $$$), our customers are happy (storage costs are down), I'm happy (fun, fun, fun). Until yesterday. Outage & Recovery: Some time after lunch we started getting reports of sluggish performance from our application, an on-demand streaming media CMS. About the same time our Cacti monitoring system sent a blizzard of emails. One of the more telling alerts was a graph of iostat await. Performance became so degraded that Pingdom began sending "server down" notifications. The overall load was moderate, there was not traffic spike. After logging onto the application servers, NFS clients of the NAS, I confirmed that just about everything was experiencing highly intermittent and insanely long IO wait times. And once I hopped onto the primary NAS node itself, the same delays were evident when trying to navigate the problem array's file system. Time to fail over, that went well. Within 20 minuts everything was confirmed to be back up and running perfectly. Post-Mortem: After any and all system failures I perform a post-mortem to determine the cause of the failure. First thing I did was ssh back into the box and start reviewing logs. It was offline, completely. Time for a trip to the data center. Hardware reset, backup an and running. In /var/syslog I found this scary looking entry: Nov 15 06:49:44 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_00], 6 Currently unreadable (pending) sectors Nov 15 06:49:44 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_07], SMART Prefailure Attribute: 1 Raw_Read_Error_Rate changed from 171 to 170 Nov 15 06:49:45 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_10], 16 Currently unreadable (pending) sectors Nov 15 06:49:45 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_10], 4 Offline uncorrectable sectors Nov 15 06:49:45 umbilo smartd[2827]: Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error Nov 15 06:49:45 umbilo smartd[2827]: # 1 Short offline Completed: read failure 90% 6576 3421766910 Nov 15 06:49:45 umbilo smartd[2827]: # 2 Short offline Completed: read failure 90% 6087 3421766910 Nov 15 06:49:45 umbilo smartd[2827]: # 3 Short offline Completed: read failure 10% 5901 656821791 Nov 15 06:49:45 umbilo smartd[2827]: # 4 Short offline Completed: read failure 90% 5818 651637856 Nov 15 06:49:45 umbilo smartd[2827]: So I went to check the Cacti graphs for the disks in the array. Here we see that, yes, disk 7 is slipping away just like syslog says it is. But we also see that disk 8's SMART Read Erros are fluctuating. There are no messages about disk 8 in syslog. More interesting is that the fluctuating values for disk 8 directly correlate to the high IO wait times! My interpretation is that: Disk 8 is experiencing an odd hardware fault that results in intermittent long operation times. Somehow this fault condition on the disk is locking up the entire array Maybe there is a more accurate or correct description, but the net result has been that the one disk is impacting the performance of the whole array. The Question(s) How can a single disk in a hardware SATA RAID-10 array bring the entire array to a screeching halt? Am I being naïve to think that the RAID card should have dealt with this? How can I prevent a single misbehaving disk from impacting the entire array? Am I missing something?

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• Where do all these messages come from?

  - by stacker

  This configuration works fine, but inbound-channel-adapter which is supposed to poll every 15 secs is running continously. Does anyone have an idea what I'm doning wrong? <si:channel id="msgChannel" /> <si:inbound-channel-adapter ref="jdbcInputAdapter" method="fetchData" channel="msgChannel"> <si:poller> <si:interval-trigger interval="15000" /> </si:poller> </si:inbound-channel-adapter> <si:outbound-channel-adapter ref="shouter" method="shout" channel="msgChannel"/>

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