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• The challenge of communicating externally with IRM secured content

  - by Simon Thorpe

  I am often asked by customers about how they handle sending IRM secured documents to external parties. Their concern is that using IRM to secure sensitive information they need to share outside their business, is troubled with the inability for third parties to install the software which enables them to gain access to the information. It is a very legitimate question and one i've had to answer many times in the past 10 years whilst helping customers plan successful IRM deployments. The operating system does not provide the required level of content security The problem arises from what IRM delivers, persistent security to your sensitive information where ever it resides and whenever it is in use. Oracle IRM gives customers an array of features that help ensure sensitive information in an IRM document or email is always protected and only accessed by authorized users using legitimate applications. Examples of such functionality are; Control of the clipboard, either by disabling completely in the opened document or by allowing the cut and pasting of information between secured IRM documents but not into insecure applications. Protection against programmatic access to the document. Office documents and PDF documents have the ability to be accessed by other applications and scripts. With Oracle IRM we have to protect against this to ensure content cannot be leaked by someone writing a simple program. Securing of decrypted content in memory. At some point during the process of opening and presenting a sealed document to an end user, we must decrypt it and give it to the application (Adobe Reader, Microsoft Word, Excel etc). This process must be secure so that someone cannot simply get access to the decrypted information. The operating system alone just doesn't have the functionality to deliver these types of features. This is why for every IRM technology there must be some extra software installed and typically this software requires administrative rights to do so. The fact is that if you want to have very strong security and access control over a document you are going to send to someone who is beyond your network infrastructure, there must be some software to provide that functionality. Simple installation with Oracle IRM The software used to control access to Oracle IRM sealed content is called the Oracle IRM Desktop. It is a small, free piece of software roughly about 12mb in size. This software delivers functionality for everything a user needs to work with an Oracle IRM solution. It provides the functionality for all formats we support, the storage and transparent synchronization of user rights and unique to Oracle, the ability to search inside sealed files stored on the local computer. In Oracle we've made every technical effort to ensure that installing this software is a simple as possible. In situations where the user's computer is part of the enterprise, this software is typically deployed using existing technologies such as Systems Management Server from Microsoft or by using Active Directory Group Policies. However when sending sealed content externally, you cannot automatically install software on the end users machine. You need to rely on them to download and install themselves. Again we've made every effort for this manual install process to be as simple as we can. Starting with the small download size of the software itself to the simple installation process, most end users are able to install and access sealed content very quickly. You can see for yourself how easily this is done by walking through our free and easy self service demonstration of using sealed content. How to handle objections and ensure there is value However the fact still remains that end users may object to installing, or may simply be unable to install the software themselves due to lack of permissions. This is often a problem with any technology that requires specialized software to access a new type of document. In Oracle, over the past 10 years, we've learned many ways to get over this barrier of getting software deployed by external users. First and I would say of most importance, is the content MUST have some value to the person you are asking to install software. Without some type of value proposition you are going to find it very difficult to get past objections to installing the IRM Desktop. Imagine if you were going to secure the weekly campus restaurant menu and send this to contractors. Their initial response will be, "why on earth are you asking me to download some software just to access your menu!?". A valid objection... there is no value to the user in doing this. Now consider the scenario where you are sending one of your contractors their employment contract which contains their address, social security number and bank account details. Are they likely to take 5 minutes to install the IRM Desktop? You bet they are, because there is real value in doing so and they understand why you are doing it. They want their personal information to be securely handled and a quick download and install of some software is a small task in comparison to dealing with the loss of this information. Be clear in communicating this value So when sending sealed content to people externally, you must be clear in communicating why you are using an IRM technology and why they need to install some software to access the content. Do not try and avoid the issue, you must be clear and upfront about it. In doing so you will significantly reduce the "I didn't know I needed to do this..." responses and also gain respect for being straight forward. One customer I worked with, 6 months after the initial deployment of Oracle IRM, called me panicking that the partner they had started to share their engineering documents with refused to install any software to access this highly confidential intellectual property. I explained they had to communicate to the partner why they were doing this. I told them to go back with the statement that "the company takes protecting its intellectual property seriously and had decided to use IRM to control access to engineering documents." and if the partner didn't respect this decision, they would find another company that would. The result? A few days later the partner had made the Oracle IRM Desktop part of their approved list of software in the company. Companies are successful when sending sealed content to third parties We have many, many customers who send sensitive content to third parties. Some customers actually sell access to Oracle IRM protected content and therefore 99% of their users are external to their business, one in particular has sold content to hundreds of thousands of external users. Oracle themselves use the technology to secure M&A documents, payroll data and security assessments which go beyond the traditional enterprise security perimeter. Pretty much every company who deploys Oracle IRM will at some point be sending those documents to people outside of the company, these customers must be successful otherwise Oracle IRM wouldn't be successful. Because our software is used by a wide variety of companies, some who use it to sell content, i've often run into people i'm sharing a sealed document with and they already have the IRM Desktop installed due to accessing content from another company. The future In summary I would say that yes, this is a hurdle that many customers are concerned about but we see much evidence that in practice, people leap that hurdle with relative ease as long as they are good at communicating the value of using IRM and also take measures to ensure end users can easily go through the process of installation. We are constantly developing new ideas to reducing this hurdle and maybe one day the operating systems will give us enough rich security functionality to have no software installation. Until then, Oracle IRM is by far the easiest solution to balance security and usability for your business. If you would like to evaluate it for yourselves, please contact us.

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• 3D Ball Physics Theory: collision response on ground and against walls?

  - by David

  I'm really struggling to get a strong grasp on how I should be handling collision response in a game engine I'm building around a 3D ball physics concept. Think Monkey Ball as an example of the type of gameplay. I am currently using sphere-to-sphere broad phase, then AABB to OBB testing (the final test I am using right now is one that checks if one of the 8 OBB points crosses the planes of the object it is testing against). This seems to work pretty well, and I am getting back: Plane that object is colliding against (with a point on the plane, the plane's normal, and the exact point of intersection. I've tried what feels like dozens of different high-level strategies for handling these collisions, without any real success. I think my biggest problem is understanding how to handle collisions against walls in the x-y axes (left/right, front/back), which I want to have elasticity, and the ground (z-axis) where I want an elastic reaction if the ball drops down, but then for it to eventually normalize and be kept "on the ground" (not go into the ground, but also not continue bouncing). Without kluging something together, I'm positive there is a good way to handle this, my theories just aren't getting me all the way there. For physics modeling and movement, I am trying to use a Euler based setup with each object maintaining a position (and destination position prior to collision detection), a velocity (which is added onto the position to determine the destination position), and an acceleration (which I use to store any player input being put on the ball, as well as gravity in the z coord). Starting from when I detect a collision, what is a good way to approach the response to get the expected behavior in all cases? Thanks in advance to anyone taking the time to assist... I am grateful for any pointers, and happy to post any additional info or code if it is useful. UPDATE Based on Steve H's and eBusiness' responses below, I have adapted my collision response to what makes a lot more sense now. It was close to right before, but I didn't have all the right pieces together at the right time! I have one problem left to solve, and that is what is causing the floor collision to hit every frame. Here's the collision response code I have now for the ball, then I'll describe the last bit I'm still struggling to understand. // if we are moving in the direction of the plane (against the normal)... if (m_velocity.dot(intersection.plane.normal) <= 0.0f) { float dampeningForce = 1.8f; // eventually create this value based on mass and acceleration // Calculate the projection velocity PVRTVec3 actingVelocity = m_velocity.project(intersection.plane.normal); m_velocity -= actingVelocity * dampeningForce; } // Clamp z-velocity to zero if we are within a certain threshold // -- NOTE: this was an experimental idea I had to solve the "jitter" bug I'll describe below float diff = 0.2f - abs(m_velocity.z); if (diff > 0.0f && diff <= 0.2f) { m_velocity.z = 0.0f; } // Take this object to its new destination position based on... // -- our pre-collision position + vector to the collision point + our new velocity after collision * time // -- remaining after the collision to finish the movement m_destPosition = m_position + intersection.diff + (m_velocity * intersection.tRemaining * GAMESTATE->dt); The above snippet is run after a collision is detected on the ball (collider) with a collidee (floor in this case). With a dampening force of 1.8f, the ball's reflected "upward" velocity will eventually be overcome by gravity, so the ball will essentially be stuck on the floor. THIS is the problem I have now... the collision code is running every frame (since the ball's z-velocity is constantly pushing it a collision with the floor below it). The ball is not technically stuck, I can move it around still, but the movement is really goofy because the velocity and position keep getting affected adversely by the above snippet. I was experimenting with an idea to clamp the z-velocity to zero if it was "close to zero", but this didn't do what I think... probably because the very next frame the ball gets a new gravity acceleration applied to its velocity regardless (which I think is good, right?). Collisions with walls are as they used to be and work very well. It's just this last bit of "stickiness" to deal with. The camera is constantly jittering up and down by extremely small fractions too when the ball is "at rest". I'll keep playing with it... I like puzzles like this, especially when I think I'm close. Any final ideas on what I could be doing wrong here? UPDATE 2 Good news - I discovered I should be subtracting the intersection.diff from the m_position (position prior to collision). The intersection.diff is my calculation of the difference in the vector of position to destPosition from the intersection point to the position. In this case, adding it was causing my ball to always go "up" just a little bit, causing the jitter. By subtracting it, and moving that clamper for the velocity.z when close to zero to being above the dot product (and changing the test from <= 0 to < 0), I now have the following: // Clamp z-velocity to zero if we are within a certain threshold float diff = 0.2f - abs(m_velocity.z); if (diff > 0.0f && diff <= 0.2f) { m_velocity.z = 0.0f; } // if we are moving in the direction of the plane (against the normal)... float dotprod = m_velocity.dot(intersection.plane.normal); if (dotprod < 0.0f) { float dampeningForce = 1.8f; // eventually create this value based on mass and acceleration? // Calculate the projection velocity PVRTVec3 actingVelocity = m_velocity.project(intersection.plane.normal); m_velocity -= actingVelocity * dampeningForce; } // Take this object to its new destination position based on... // -- our pre-collision position + vector to the collision point + our new velocity after collision * time // -- remaining after the collision to finish the movement m_destPosition = m_position - intersection.diff + (m_velocity * intersection.tRemaining * GAMESTATE->dt); UpdateWorldMatrix(m_destWorldMatrix, m_destOBB, m_destPosition, false); This is MUCH better. No jitter, and the ball now "rests" at the floor, while still bouncing off the floor and walls. The ONLY thing left is that the ball is now virtually "stuck". He can move but at a much slower rate, likely because the else of my dot product test is only letting the ball move at a rate multiplied against the tRemaining... I think this is a better solution than I had previously, but still somehow not the right idea. BTW, I'm trying to journal my progress through this problem for anyone else with a similar situation - hopefully it will serve as some help, as many similar posts have for me over the years.

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• how to do event checks for loops?

  - by yao jiang

  I am having some trouble getting the logic down for this. Currently, I have an app that animates the astar pathfinding algorithm. On start of the app, the ui will show the following: User can press "space" to randomly choose start/end coords, then the app will animate it. Or, user can choose the start/end by left-click/right-click. During the animation, the user can also left-click to generate blocks, or right-click to choose a new destiantion. Where I am stuck at is how to handle the events while the app is animating. Right now, I am checking events in the main loop, then when the app is animating, I do event checks again. While it works fine, I feel that I am probably doing it wrong. What is the proper way of setting up the main loop that will handle the events while the app is animating? In main loop, the app start animating once user choose start/end. In my draw function, I am putting another event checker in there. def clear(rows): for r in range(rows): for c in range(rows): if r%3 == 1 and c%3 == 1: color = brown; grid[r][c] = 1; buildCoor.append(r); buildCoor.append(c); else: color = white; grid[r][c] = 0; pick_image(screen, color, width*c, height*r); pygame.display.flip(); os.system('cls'); # draw out the grid def draw(start, end, grid, route_coord): # draw the end coords color = red; pick_image(screen, color, width*end[1],height*end[0]); pygame.display.flip(); # then draw the rest of the route for i in range(len(route_coord)): # pausing because we want animation time.sleep(speed); # get the x/y coords x,y = route_coord[i]; event_on = False; if grid[x][y] == 2: color = green; elif grid[x][y] == 3: color = blue; for event in pygame.event.get(): if event.type == pygame.MOUSEBUTTONDOWN: if event.button == 3: print "destination change detected, rerouting"; # get mouse position, px coords pos = pygame.mouse.get_pos(); # get grid coord c = pos[0] // width; r = pos[1] // height; grid[r][c] = 4; end = [r, c]; elif event.button == 1: print "user generated event"; pos = pygame.mouse.get_pos(); # get grid coord c = pos[0] // width; r = pos[1] // height; # mark it as a block for now grid[r][c] = 1; event_on = True; if check_events([x,y]) or event_on: # there is an event # mark it as a block for now grid[y][x] = 1; pick_image(screen, event_x, width*y, height*x); pygame.display.flip(); # then find a new route new_start = route_coord[i-1]; marked_grid, route_coord = find_route(new_start, end, grid); draw(new_start, end, grid, route_coord); return; # just end draw here so it wont throw the "index out of range" error elif grid[x][y] == 4: color = red; pick_image(screen, color, width*y, height*x); pygame.display.flip(); # clear route coord list, otherwise itll just add more unwanted coords route_coord_list[:] = []; clear(rows); # main loop while not done: # check the events for event in pygame.event.get(): # mouse events if event.type == pygame.MOUSEBUTTONDOWN: # get mouse position, px coords pos = pygame.mouse.get_pos(); # get grid coord c = pos[0] // width; r = pos[1] // height; # find which button pressed, highlight grid accordingly if event.button == 1: # left click, start coords if grid[r][c] == 2: grid[r][c] = 0; color = white; elif grid[r][c] == 0 or grid[r][c] == 4: grid[r][c] = 2; start = [r,c]; color = green; else: grid[r][c] = 1; color = brown; elif event.button == 3: # right click, end coords if grid[r][c] == 4: grid[r][c] = 0; color = white; elif grid[r][c] == 0 or grid[r][c] == 2: grid[r][c] = 4; end = [r,c]; color = red; else: grid[r][c] = 1; color = brown; pick_image(screen, color, width*c, height*r); # keyboard events elif event.type == pygame.KEYDOWN: clear(rows); # one way to quit program if event.key == pygame.K_ESCAPE: print "program will now exit."; done = True; # space key for random start/end elif event.key == pygame.K_SPACE: # first clear the ui clear(rows); # now choose random start/end coords buildLoc = zip(buildCoor,buildCoor[1:])[::2]; #print buildLoc; (start_x, start_y, end_x, end_y) = pick_point(); while (start_x, start_y) in buildLoc or (end_x, end_y) in buildLoc: (start_x, start_y, end_x, end_y) = pick_point(); clear(rows); print "chosen random start/end coords: ", (start_x, start_y, end_x, end_y); if (start_x, start_y) in buildLoc or (end_x, end_y) in buildLoc: print "error"; # draw the route marked_grid, route_coord = find_route([start_x,start_y],[end_x,end_y], grid); draw([start_x, start_y], [end_x, end_y], marked_grid, route_coord); # return key for user defined start/end elif event.key == pygame.K_RETURN: # first clear the ui clear(rows); # get the user defined start/end print "user defined start/end are: ", (start[0], start[1], end[0], end[1]); grid[start[0]][start[1]] = 1; grid[end[0]][end[1]] = 2; # draw the route marked_grid, route_coord = find_route(start, end, grid); draw(start, end, marked_grid, route_coord); # c to clear the screen elif event.key == pygame.K_c: print "clearing screen."; clear(rows); # go fullscreen elif event.key == pygame.K_f: if not full_sc: pygame.display.set_mode([1366, 768], pygame.FULLSCREEN); full_sc = True; rows = 15; clear(rows); else: pygame.display.set_mode(size); full_sc = False; # +/- key to change speed of animation elif event.key == pygame.K_LEFTBRACKET: if speed >= 0.1: print SPEED_UP; speed = speed_up(speed); print speed; else: print FASTEST; print speed; elif event.key == pygame.K_RIGHTBRACKET: if speed < 1.0: print SPEED_DOWN; speed = slow_down(speed); print speed; else: print SLOWEST print speed; # second method to quit program elif event.type == pygame.QUIT: print "program will now exit."; done = True; # limit to 20 fps clock.tick(20); # update the screen pygame.display.flip();

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• C#/.NET Little Wonders: Comparer&lt;T&gt;.Default

  - by James Michael Hare

  I’ve been working with a wonderful team on a major release where I work, which has had the side-effect of occupying most of my spare time preparing, testing, and monitoring.  However, I do have this Little Wonder tidbit to offer today. Introduction The IComparable<T> interface is great for implementing a natural order for a data type.  It’s a very simple interface with a single method: 1: public interface IComparer<in T> 2: { 3: // Compare two instances of same type. 4: int Compare(T x, T y); 5: }  So what do we expect for the integer return value?  It’s a pseudo-relative measure of the ordering of x and y, which returns an integer value in much the same way C++ returns an integer result from the strcmp() c-style string comparison function: If x == y, returns 0. If x > y, returns > 0 (often +1, but not guaranteed) If x < y, returns < 0 (often –1, but not guaranteed) Notice that the comparison operator used to evaluate against zero should be the same comparison operator you’d use as the comparison operator between x and y.  That is, if you want to see if x > y you’d see if the result > 0. The Problem: Comparing With null Can Be Messy This gets tricky though when you have null arguments.  According to the MSDN, a null value should be considered equal to a null value, and a null value should be less than a non-null value.  So taking this into account we’d expect this instead: If x == y (or both null), return 0. If x > y (or y only is null), return > 0. If x < y (or x only is null), return < 0. But here’s the problem – if x is null, what happens when we attempt to call CompareTo() off of x? 1: // what happens if x is null? 2: x.CompareTo(y); It’s pretty obvious we’ll get a NullReferenceException here.  Now, we could guard against this before calling CompareTo(): 1: int result; 2:  3: // first check to see if lhs is null. 4: if (x == null) 5: { 6: // if lhs null, check rhs to decide on return value. 7: if (y == null) 8: { 9: result = 0; 10: } 11: else 12: { 13: result = -1; 14: } 15: } 16: else 17: { 18: // CompareTo() should handle a null y correctly and return > 0 if so. 19: result = x.CompareTo(y); 20: } Of course, we could shorten this with the ternary operator (?:), but even then it’s ugly repetitive code: 1: int result = (x == null) 2: ? ((y == null) ? 0 : -1) 3: : x.CompareTo(y); Fortunately, the null issues can be cleaned up by drafting in an external Comparer.  The Soltuion: Comparer<T>.Default You can always develop your own instance of IComparer<T> for the job of comparing two items of the same type.  The nice thing about a IComparer is its is independent of the things you are comparing, so this makes it great for comparing in an alternative order to the natural order of items, or when one or both of the items may be null. 1: public class NullableIntComparer : IComparer<int?> 2: { 3: public int Compare(int? x, int? y) 4: { 5: return (x == null) 6: ? ((y == null) ? 0 : -1) 7: : x.Value.CompareTo(y); 8: } 9: }  Now, if you want a custom sort -- especially on large-grained objects with different possible sort fields -- this is the best option you have.  But if you just want to take advantage of the natural ordering of the type, there is an easier way.  If the type you want to compare already implements IComparable<T> or if the type is System.Nullable<T> where T implements IComparable, there is a class in the System.Collections.Generic namespace called Comparer<T> which exposes a property called Default that will create a singleton that represents the default comparer for items of that type.  For example: 1: // compares integers 2: var intComparer = Comparer<int>.Default; 3:  4: // compares DateTime values 5: var dateTimeComparer = Comparer<DateTime>.Default; 6:  7: // compares nullable doubles using the null rules! 8: var nullableDoubleComparer = Comparer<double?>.Default;  This helps you avoid having to remember the messy null logic and makes it to compare objects where you don’t know if one or more of the values is null. This works especially well when creating say an IComparer<T> implementation for a large-grained class that may or may not contain a field.  For example, let’s say you want to create a sorting comparer for a stock open price, but if the market the stock is trading in hasn’t opened yet, the open price will be null.  We could handle this (assuming a reasonable Quote definition) like: 1: public class Quote 2: { 3: // the opening price of the symbol quoted 4: public double? Open { get; set; } 5:  6: // ticker symbol 7: public string Symbol { get; set; } 8:  9: // etc. 10: } 11:  12: public class OpenPriceQuoteComparer : IComparer<Quote> 13: { 14: // Compares two quotes by opening price 15: public int Compare(Quote x, Quote y) 16: { 17: return Comparer<double?>.Default.Compare(x.Open, y.Open); 18: } 19: } Summary Defining a custom comparer is often needed for non-natural ordering or defining alternative orderings, but when you just want to compare two items that are IComparable<T> and account for null behavior, you can use the Comparer<T>.Default comparer generator and you’ll never have to worry about correct null value sorting again.     Technorati Tags: C#,.NET,Little Wonders,BlackRabbitCoder,IComparable,Comparer

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• Master-slave vs. peer-to-peer archictecture: benefits and problems

  - by Ashok_Ora

  Normal 0 false false false EN-US X-NONE X-NONE Almost two decades ago, I was a member of a database development team that introduced adaptive locking. Locking, the most popular concurrency control technique in database systems, is pessimistic. Locking ensures that two or more conflicting operations on the same data item don’t “trample” on each other’s toes, resulting in data corruption. In a nutshell, here’s the issue we were trying to address. In everyday life, traffic lights serve the same purpose. They ensure that traffic flows smoothly and when everyone follows the rules, there are no accidents at intersections. As I mentioned earlier, the problem with typical locking protocols is that they are pessimistic. Regardless of whether there is another conflicting operation in the system or not, you have to hold a lock! Acquiring and releasing locks can be quite expensive, depending on how many objects the transaction touches. Every transaction has to pay this penalty. To use the earlier traffic light analogy, if you have ever waited at a red light in the middle of nowhere with no one on the road, wondering why you need to wait when there’s clearly no danger of a collision, you know what I mean. The adaptive locking scheme that we invented was able to minimize the number of locks that a transaction held, by detecting whether there were one or more transactions that needed conflicting eyou could get by without holding any lock at all. In many “well-behaved” workloads, there are few conflicts, so this optimization is a huge win. If, on the other hand, there are many concurrent, conflicting requests, the algorithm gracefully degrades to the “normal” behavior with minimal cost. We were able to reduce the number of lock requests per TPC-B transaction from 178 requests down to 2! Wow! This is a dramatic improvement in concurrency as well as transaction latency. The lesson from this exercise was that if you can identify the common scenario and optimize for that case so that only the uncommon scenarios are more expensive, you can make dramatic improvements in performance without sacrificing correctness. So how does this relate to the architecture and design of some of the modern NoSQL systems? NoSQL systems can be broadly classified as master-slave sharded, or peer-to-peer sharded systems. NoSQL systems with a peer-to-peer architecture have an interesting way of handling changes. Whenever an item is changed, the client (or an intermediary) propagates the changes synchronously or asynchronously to multiple copies (for availability) of the data. Since the change can be propagated asynchronously, during some interval in time, it will be the case that some copies have received the update, and others haven’t. What happens if someone tries to read the item during this interval? The client in a peer-to-peer system will fetch the same item from multiple copies and compare them to each other. If they’re all the same, then every copy that was queried has the same (and up-to-date) value of the data item, so all’s good. If not, then the system provides a mechanism to reconcile the discrepancy and to update stale copies. So what’s the problem with this? There are two major issues: First, IT’S HORRIBLY PESSIMISTIC because, in the common case, it is unlikely that the same data item will be updated and read from different locations at around the same time! For every read operation, you have to read from multiple copies. That’s a pretty expensive, especially if the data are stored in multiple geographically separate locations and network latencies are high. Second, if the copies are not all the same, the application has to reconcile the differences and propagate the correct value to the out-dated copies. This means that the application program has to handle discrepancies in the different versions of the data item and resolve the issue (which can further add to cost and operation latency). Resolving discrepancies is only one part of the problem. What if the same data item was updated independently on two different nodes (copies)? In that case, due to the asynchronous nature of change propagation, you might land up with different versions of the data item in different copies. In this case, the application program also has to resolve conflicts and then propagate the correct value to the copies that are out-dated or have incorrect versions. This can get really complicated. My hunch is that there are many peer-to-peer-based applications that don’t handle this correctly, and worse, don’t even know it. Imagine have 100s of millions of records in your database – how can you tell whether a particular data item is incorrect or out of date? And what price are you willing to pay for ensuring that the data can be trusted? Multiple network messages per read request? Discrepancy and conflict resolution logic in the application, and potentially, additional messages? All this overhead, when all you were trying to do was to read a data item. Wouldn’t it be simpler to avoid this problem in the first place? Master-slave architectures like the Oracle NoSQL Database handles this very elegantly. A change to a data item is always sent to the master copy. Consequently, the master copy always has the most current and authoritative version of the data item. The master is also responsible for propagating the change to the other copies (for availability and read scalability). Client drivers are aware of master copies and replicas, and client drivers are also aware of the “currency” of a replica. In other words, each NoSQL Database client knows how stale a replica is. This vastly simplifies the job of the application developer. If the application needs the most current version of the data item, the client driver will automatically route the request to the master copy. If the application is willing to tolerate some staleness of data (e.g. a version that is no more than 1 second out of date), the client can easily determine which replica (or set of replicas) can satisfy the request, and route the request to the most efficient copy. This results in a dramatic simplification in application logic and also minimizes network requests (the driver will only send the request to exactl the right replica, not many). So, back to my original point. A well designed and well architected system minimizes or eliminates unnecessary overhead and avoids pessimistic algorithms wherever possible in order to deliver a highly efficient and high performance system. If you’ve every programmed an Oracle NoSQL Database application, you’ll know the difference! /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

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• OS8- AK8- The bad news...

  - by Steve Tunstall

  Ok I told you I would give you the bad news of AK8 to go along with all the cool new stuff, so here it is. It's not that bad, really, just things you need to be aware of. First, the 2013.1 code is being called OS8, AK8 and 2013.1 by different people. I mean different people INSIDE Oracle!! It was supposed to be easy, but it never is. So for the rest of this blog entry, I'm calling it AK8. AK8 is not compatible with the 7x10 series. Ever. The 7x10 series is not supported with AK8, and if you try to upgrade one, it will fail at the healthcheck. All 7x20 series, all of them regardless of age, are supported with AK8. Drive trays. Let's talk about drive trays and SAS cards. The older drive trays for the 7x20 series were called the "Riverwalk 2" or "DS2" trays. They were technically the "J4410" series JBODs that Sun used to sell a la carte before we stopped selling JBODs. Don't get me started on that, it still makes me mad. We used these for many years, and you can still buy them right now until December 15th, 2013, when they will no longer be sold. The DS2 tray only came as a 4u, 24 drive shelf. It held 3.5" drives, and you had a choice of 2TB, 3TB, 300GB or 600GB drives. The SAS HBA in the 7x20 series was called a "Thebe" card, with a part # of 7105394. The 7420, for example, came standard with two of these "Thebe" cards for connecting to the disk trays. Two Thebe cards could handle up to 12 trays, so one would add two more cards to go to 24 trays, or have up to six Thebe cards to handle 36 trays. This card was for external SAS only. It did not connect to the internal OS drives or the Readzillas, both of which used the internal SCSI controller of the server. These Riverwalk 2 trays ARE supported with AK8. You can upgrade your older 7420 or 7320, no problem, as-is. The much older Riverwalk 1 trays or J4400 trays are NOT supported by AK8. However, they were only used by the 7x10 series, and we already said that the 7x10 series was not supported. Here's where it gets tricky. Since last January, we have been selling the new style disk trays. We call them the "DE2-24P" and the "DE2-24C" trays. The "C" tray is for capacity drives, which are 3.5" 3TB or 4TB drives. The "P" trays are for performance drives, which are 2.5" 300GB and 900GB drives. These trays are NOT Riverwalk 2 trays, even though the "C" series may kind of look like it. Different manufacturer and different firmware. They are not new. Like I said, we've been selling them with the 7x20 series since last January. They are the only disk trays we will be selling going forward. Of course, AK8 supports them. So what's the problem? The problem is going to be for people who have to mix drive trays. Remember, your older 7x20 series has Thebe SAS2 HBAs. These have 2 SAS ports per card.  The new ZS3-2 and ZS3-4 systems, however, have the new "Thebe2" SAS2 HBAs. These Thebe2 cards have 4 ports per card. This is very cool, as we can now do more SAS channels with less cards. Instead of needing 4 SAS cards to grow to 24 trays like we did with the old Thebe cards, I can now do 24 trays with only 2 Thebe2 cards. This means more IO slots for fun things like Infiniband and 10G. So far, so good, right? These Thebe2 cards work with any disk tray. You can even mix older DS2 trays with the newer DE2 trays in the same system, as long as you have Thebe2 cards. Ah, there's your problem. You don't have Thebe2 cards in your old 7420, do you? Well, I told you the bad news wasn't that bad, right? We can take out your Thebe cards and replace them with Thebe2. You can then plug your older DS2 trays right back in, and also now get newer DE2 trays going forward. However, it's important that the trays are on different SAS channels. You can mix them in the same system, but not on the same channel. Ask your local SC if you need help with the new cable layout. By the way, the new ZS3-2 and ZS3-4 systems also include a new IO card called "Erie" cards. These are for INTERNAL SAS to the OS drives and the Readzillas. So those are now SAS2 instead of SATA like the older models. Yes, the Erie card uses an IO slot, but that's OK, because the Thebe2 cards allow us to use less SAS HBAs to grow the system, right? That's it. Not too much bad news and really not that bad. AK8 does not support the 7x10 series, and you may need new Thebe2 cards in your older systems if you want to add on newer DE2 trays. I think we can all agree that there are worse things out there. Like our Congress.   Next up.... More good news and cool AK8 tricks. Such as virtual NICS. 

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• Adding multiple data importers support to web applications

  - by DigiMortal

  I’m building web application for customer and there is requirement that users must be able to import data in different formats. Today we will support XLSX and ODF as import formats and some other formats are waiting. I wanted to be able to add new importers on the fly so I don’t have to deploy web application again when I add new importer or change some existing one. In this posting I will show you how to build generic importers support to your web application. Importer interface All importers we use must have something in common so we can easily detect them. To keep things simple I will use interface here. public interface IMyImporter {     string[] SupportedFileExtensions { get; }     ImportResult Import(Stream fileStream, string fileExtension); } Our interface has the following members: SupportedFileExtensions – string array of file extensions that importer supports. This property helps us find out what import formats are available and which importer to use with given format. Import – method that does the actual importing work. Besides file we give in as stream we also give file extension so importer can decide how to handle the file. It is enough to get started. When building real importers I am sure you will switch over to abstract base class. Importer class Here is sample importer that imports data from Excel and Word documents. Importer class with no implementation details looks like this: public class MyOpenXmlImporter : IMyImporter {     public string[] SupportedFileExtensions     {         get { return new[] { "xlsx", "docx" }; }     }     public ImportResult Import(Stream fileStream, string extension)     {         // ...     } } Finding supported import formats in web application Now we have importers created and it’s time to add them to web application. Usually we have one page or ASP.NET MVC controller where we need importers. To this page or controller we add the following method that uses reflection to find all classes that implement our IMyImporter interface. private static string[] GetImporterFileExtensions() {     var types = from a in AppDomain.CurrentDomain.GetAssemblies()                 from t in a.GetTypes()                 where t.GetInterfaces().Contains(typeof(IMyImporter))                 select t;       var extensions = new Collection<string>();     foreach (var type in types)     {         var instance = (IMyImporter)type.InvokeMember(null,                        BindingFlags.CreateInstance, null, null, null);           foreach (var extension in instance.SupportedFileExtensions)         {             if (extensions.Contains(extension))                 continue;               extensions.Add(extension);         }     }       return extensions.ToArray(); } This code doesn’t look nice and is far from optimal but it works for us now. It is possible to improve performance of web application if we cache extensions and their corresponding types to some static dictionary. We have to fill it only once because our application is restarted when something changes in bin folder. Finding importer by extension When user uploads file we need to detect the extension of file and find the importer that supports given extension. We add another method to our page or controller that uses reflection to return us importer instance or null if extension is not supported. private static IMyImporter GetImporterForExtension(string extensionToFind) {     var types = from a in AppDomain.CurrentDomain.GetAssemblies()                 from t in a.GetTypes()                 where t.GetInterfaces().Contains(typeof(IMyImporter))                 select t;     foreach (var type in types)     {         var instance = (IMyImporter)type.InvokeMember(null,                        BindingFlags.CreateInstance, null, null, null);           if (instance.SupportedFileExtensions.Contains(extensionToFind))         {             return instance;         }     }       return null; } Here is example ASP.NET MVC controller action that accepts uploaded file, finds importer that can handle file and imports data. Again, this is sample code I kept minimal to better illustrate how things work. public ActionResult Import(MyImporterModel model) {     var file = Request.Files[0];     var extension = Path.GetExtension(file.FileName).ToLower();     var importer = GetImporterForExtension(extension.Substring(1));     var result = importer.Import(file.InputStream, extension);     if (result.Errors.Count > 0)     {         foreach (var error in result.Errors)             ModelState.AddModelError("file", error);           return Import();     }     return RedirectToAction("Index"); } Conclusion That’s it. Using couple of ugly methods and one simple interface we were able to add importers support to our web application. Example code here is not perfect but it works. It is possible to cache mappings between file extensions and importer types to some static variable because changing of these mappings means that something is changed in bin folder of web application and web application is restarted in this case anyway.

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• IIS, multiple CPU cores, application pools and worker processes - best configuration for a single si

  - by Egghead Design

  Hi We use Kentico CMS and I've exchanged emails with them about a web garden deployment. We have a single site running on a server with 8 cpu cores. In line with Kentico's advice, we have not altered the application pool web garden setting from the default i.e. it is set to a maximum number of worker processes of 1. Our experience is that the site only uses one of the cpu cores - the others are idling. When I emailed them about this, their response was that the OS/IIS would handle this and use other cores as necessary even though the application pool only has a single worker process. Now, I've a lot of respect for the guys at Kentico, but this doesn't seem right to me? Surely, if we want to use all cores, we need to permit eight worker processes (and implement session state storage in SQL server)? Many thanks Tony

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• Retrieve user details from Active Directory using SID

  - by er4z0r

  Hi, How can I find a user in my AD when I have his/her SID. I don't want to rely on other attributes, since I am trying to detect changes to these. Example: I get a message about a change to user record containing: Message: User Account Changed: Target Account Name: test12 Target Domain: DOMAIN Target Account ID: %{S-1-5-21-3968247570-3627839482-368725868-1110} Caller User Name: Administrator Caller Domain: DOMAIN Caller Logon ID: (0x0,0x62AB1) Privileges: - I want to notify the user about the change. So I need their account-information from AD. When I try to retrieve the user's data from AD via VBScript like this: Wscript.StdOut.writeLine "Found an Account ID: " & objMatch.value Set objUser = GetObject("LDAP://GUID=1521396824757036278394823687258681110") Wscript.StdOut.writeLine objUser I receive an error stating The handle is invalid Code:80070006

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• Cheap dvr media server

  - by Tester101

  I would like to build a new computer to be used as a DVR and media server. I am thinking of using mythtv as the DVR software, but short of that decision I am completely open to suggestions. Requirements: Must be cheap. Must have low power consumption (since it will always be on). Should be quiet. Should be small. I'm really not sure where to start with this project, and am open to any hardware/software suggestions. Is it possible to build a small quiet and cheap system? *Keep in mind I am working on this project because I am tired of Cable rate increases, but I can't imagine living without a DVR so cost is very important and I would like the system to be sub $200.00. The system also needs to handle the new digital broadcast system. Thanks for the help,

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• Remove Dell Openmanage from Windows 2008

  - by Erwin Blonk

  I have installed Dell Openmanage Server Agent 4.2.2 on Windows Server 2008. I need the newer version, so I need to install this version first. However, outside some registry references pointing to sources that aren't there, there is little or no trace of it being installed. For example, no trace of the program files or an entry in Prgrams And Features. Still, installing a newer version keeps coming up with an older version that needs to be removed first. When I try to install version 4.2.2 to repair and eventually remove it, it gives an error: Dell Openmanage Server Agent - Error An error was encountered while testing machine type. Failure openingen required handle to .DLL. Dell Openmanage Server Agent cannot continue the installation. Setup will exit now. I haven't found anything using different parts of the error messages as search terms.

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• STUN-server using AWS

  - by Yrlec

  We are about to hire some consultants to help us set up an AWS-based server environment that will enable us to handle NAT Traversal for our P2P application. One important part of the NAT Traversal infrastructure is the STUN-server (http://en.wikipedia.org/wiki/STUN). They just told us that in order for the STUN-server to work you must have two public static IP-addresses pointing to the same server. To more specific they said this: It appears that you need 2 static IPs for each server for the STUN to work. Please note, these IPs have to be put into the configuration file, therefore, each time you restart the instance you have to make sure you either use the same IPs or you have to update configuration. As you plan to use AWS for your installation, please confirm that you can have 2 static IP for each server. Our question is if this is possible using AWS and if so, how? If not, do you know any other way to set up a STUN-server using AWS?

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• Dual Exchange 2010 on different VM + single public IP + multiple domains

  - by Shivan Raptor

  Here is the scenario: I have 2 Exchange Server 2010 on 2 different Virtual Machines, created by and based on Hyper-V. They have IP and domain: 192.168.5.11, domainA.com ; and 192.168.5.12, domainB.com respectively. The problem is, I only have 1 public IP, say 123.123.1.1 . How do I configure the settings so that I can successfully receive emails using both Exchange servers? Given that I cannot use single Exchange server for multiple domains. -- UPDATE -- To clarify, the domainA.com and domainB.com mentioned above are website domains, instead of multiple Active Directory forests. Users of the two Exchange Server shares the same Active Directory. I know that ONE Exchange Server can handle multiple domains, but I would like to separate them into different Virtual Machines, for load balancing and data separation.

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• Google's Search Box in SharePoint

  - by Evan M.

  Has anyone here looked at the Google Search Box for SharePoint? We're looking into it as part of our MOSS deployment since we also use Google's GSA, and I'm personally not impressed with it, while a colleague seems to think that it's the only option we should be using, or even considering. While I've got no problems with the GSA indexing our SharePoint content, the Search Box just seems clumsy. It looks horrible, the results being returned are much more limited than what I get if I use the GSA search page itself, configuring it has been nothing but a PITA and it's still only got a basic config ans isn't respecting things like user permissions or search scopes that the default SharePoint Indexer and search controls handle out of the box. What are your guys thoughts? Am I being overly critical, and should just spend more time trying to configure it? Are you using a split-personality with it yourself, where you have the GSA for enterprise wide search, but use SharePoint for local searches? Other thoughts?

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• How to configure Apache so all requests go to single CGI file

  - by fastmonkeywheels

  I'm porting a CGI application from an embedded web server to run under Apache. In the effort of changing the least amount required I'm trying to figure out how to configure Apache so any requests coming in go to my CGI program, which then will use the QueryString environmental variable to determine which file needs to be created. I have Apache working now to where it will process my CGI file if it's requested directly i.e. localhost/cgi-bin/cgi_test.out but I need to figure out how to get my application to be called whenever any file is requested: localhost/ - call my application with QueryString set to "" or "/" localhost/thisFile - call my application with QueryString set to "/thisFile" etc. I have been doing all of my configuration testing under /etc/apache2/sites-available/mysite, which has been enabled and the default disabled. Thanks for any help. I've tried the recommendation from here: http://serverfault.com/questions/56082/configure-apache-to-handle-all-requests-via-single-index-php but I keep getting circular redirects.

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• Server overloaded with log messages: tty_release_dev: pts0: read/write wait queue active!

  - by Raph

  In the logs, I have this (extract from the full kernel messages logges at 06:01:14): Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.863038] BUG: unable to handle kernel NULL pointer dereference at 0000000000000015 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861081] Process telnet (pid: 20247, threadinfo ffff8800f8598000, task ffff8800024d4500) And then the server logs flooded by this message: Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861547] tty_release_dev: pts0: read/write wait queue active! In the end, 2 hours later, I had to reboot because it had become inaccessible: the load hat grown to 160%. The last command does not show anyone logged on pts0 at that time. I also don't know where this telnet process could come from.... This is an AWS instance running UBUNTU 10.04 LTS And here are the complete logs: Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.863038] BUG: unable to handle kernel NULL pointer dereference at 0000000000000015 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861007] IP: [<ffffffff81363dde>] n_tty_read+0x2ce/0x970 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861019] PGD ee13d067 PUD f8698067 PMD 0 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861025] Oops: 0000 [#1] SMP Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861028] last sysfs file: /sys/devices/xen/vbd-2208/block/sdk/removable Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861032] CPU 0 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861034] Modules linked in: ipv6 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861040] Pid: 20247, comm: telnet Not tainted 2.6.32-312-ec2 #24-Ubuntu Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861042] RIP: e030:[<ffffffff81363dde>] [<ffffffff81363dde>] n_tty_read+0x2ce/0x970 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861047] RSP: e02b:ffff8800f8599d88 EFLAGS: 00010246 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861049] RAX: 0000000000000015 RBX: ffff8800f8598000 RCX: 0000000001aed069 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861052] RDX: 0000000000000000 RSI: ffff8800f8599e67 RDI: ffff8801dd833d1c Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861054] RBP: ffff8800f8599e98 R08: ffffffff8135eb10 R09: 7fffffffffffffff Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861057] R10: 0000000000000000 R11: 0000000000000246 R12: ffff8801dd833800 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861059] R13: 0000000000000000 R14: ffff8801dd833a68 R15: ffff8801dd833d1c Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861065] FS: 00007f90121f6720(0000) GS:ffff880002c40000(0000) knlGS:0000000000000000 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861068] CS: e033 DS: 0000 ES: 0000 CR0: 000000008005003b Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861070] CR2: 0000000000000015 CR3: 0000000032a59000 CR4: 0000000000002660 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861073] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861076] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861081] Process telnet (pid: 20247, threadinfo ffff8800f8598000, task ffff8800024d4500) Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861083] Stack: Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861085] 0000000000000000 0000000001aed069 ffff8801dd8339c8 ffff8800024d4500 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861089] <0> ffff8801dd8339c0 ffff8801dd833c90 0000000001aed027 ffff8800024d4500 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861094] <0> ffff8801dd8338d8 0000000000000000 ffff8800024d4500 0000000000000000 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861099] Call Trace: Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861107] [<ffffffff81034bc0>] ? default_wake_function+0x0/0x10 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861113] [<ffffffff8135ebb6>] tty_read+0xa6/0xf0 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861118] [<ffffffff810ee7e5>] vfs_read+0xb5/0x1a0 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861122] [<ffffffff810ee91c>] sys_read+0x4c/0x80 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861127] [<ffffffff81009ba8>] system_call_fastpath+0x16/0x1b Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861131] [<ffffffff81009b40>] ? system_call+0x0/0x52 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861133] Code: 85 d2 0f 84 92 00 00 00 45 8b ac 24 5c 02 00 00 f0 45 0f b3 2e 45 19 ed 49 63 84 24 5c 02 00 00 49 8b 94 24 50 02 00 00 4c 89 ff <0f> be 1c 02 e8 a9 d3 14 00 41 8b 94 24 5c 02 00 00 41 83 ac 24 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861171] RIP [<ffffffff81363dde>] n_tty_read+0x2ce/0x970 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861175] RSP <ffff8800f8599d88> Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861171] RIP [<ffffffff81363dde>] n_tty_read+0x2ce/0x970 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861175] RSP <ffff8800f8599d88> Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861177] CR2: 0000000000000015 Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861205] ---[ end trace f10eee2057ff4f6b ]--- Apr 21 06:01:14 ip-10-49-109-107 kernel: [233185.861547] tty_release_dev: pts0: read/write wait queue active!

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• VMFS recovery - how do you proceed?

  - by ToreTrygg

  The more I look into ESX the more often i have to handle cases where the partition table of a disk with a VMFS volume gets corrupted. The reasons for this can be * idiot user * failed update * power failure * .... I guess you guys must already have something like a usual procedure on how to work through this cases. I am especially interested in a straight fast way to find out if the VMFS volume itself is corrupted beyond repair. So far I use very time consuming attempts with scans with Testdisk and similar tools. Do you have better / faster ways ?

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• Google Contacts and Mac OS X Address Book

  - by dyve

  The sync that Google offers for Google Contacts < Mac OS X Address Book is seriously flawed. It doesn't sync automatically, it doesn't sync all contacts, it doesn't sync all fields. See here for a list of warnings and issues. Is there a better way to sync Google Contacts to Mac Address Book bidirectionally? Preferably free, and preferably without adding extra software. I have tried to do it through Plaxo (which has an excellent Mac Address Book sync, albeit through an extra software install), but Plaxo doesn't handle Google Sync well (no updates). UPDATE: For the new Mac OS X Snow Leopard this shouldn't be an issue. This question is looking for a Leopard answer.

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• Bridging with aliased Ethernet card for Virtualizing with single Ethernet card

  - by user113505

  We are having a server with good CPU and RAM,so we are planning to do XEN virtualization on ubuntu 12.04 server to handle high traffic. The plan is to keep the host machine only to manage VMs(no NAT ing). A New public IP will be assigned to that VM,For that i think we need a Bridge to external network(Since my Machine has only single ethernet card aliased with 4 different Pub IP's) Is it possible to create a bridge using aliased IP single ethernet card aliased to 4 pub IPs Do we need an additional Ethernet card to do Bridging.Only have ssh access to the machine. Any suggestions will be appreciated.

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• GET /wpad.dat entries flooding my access_log

  - by Aas

  I have a small LAN of some 30 users in it with proxy auto configuration enabled and working. Two of them are requesting wpad.dat file too rapidly at a pace of 30 times per second. 10.1.14.246 - - [02/Jun/2014:09:07:18 +0200] "GET /wpad.dat HTTP/1.1" 302 302 10.1.14.141 - - [02/Jun/2014:09:07:18 +0200] "GET /wpad.dat HTTP/1.1" 302 302 I don't know whether this is a problem from performance perspective, (the server is powerful enough to handle this) but the problem is it clogs up the access_log file. It grows about 1GB per week. Clients run Win7Pro. What could cause this behavior? What can be done to stop it? I have shortened log rotate window as a temporary workaround to prevent /var fill up. Thanks beforehand for your support.

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• Offset the tickmarks of a secondary axis

  - by Dan

  I would like to offset the tickmarks of a secondary axis in excel WITHOUT changing the minimum. Here is a very complicated VBA class that apparently solves the issue but I would like a solution that doesn't require me to construct my entire chart in VBA. Here is an example of what I mean (I removed the chart insides so it looks funny, but really only the axes matter for this question): I am happy with the primary axis on the left. The secondary axis is just the primary axis plus 7.96%, so the secondary axis HAS TO have 0.0796 as a minimum. But I would like my tickmarks to be at nice rounder numbers so I would like to offset the starting point of the secondary axis' tickmarks to only start at 8%. Does anyone know of a way to achieve this? Just to be clear about the VBA, I am happy to use a VBA solution but I don't have the time to actually construct the chart itself in VBA. Using VBA to get a handle on the chart and make the adjustment would be perfect.

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• upgrade glibc on RHEL4 without breaking anything

  - by SpliFF

  I have a static version of wkhtmltopdf which requires glibc-2.4 wkhtmltopdf: /lib/tls/libc.so.6: version `GLIBC_2.4' not found (required by wkhtmltopdf) I have apt installed with the DAG repos. Other than that the server is pretty stock standard except for Coldfusion MX7. My question is, is it safe to just "apt update glibc"? Will the updated glibc clobber the old one or will they co-exist? Should I "apt upgrade" the whole server? I'm pretty sure everything else (Apache2, Postgres8, etc) will handle the upgrade but Coldfusion concerns me due to its proprietry nature.

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• What's a good, affortable router that will not give me problems when downloading torrents?

  - by Lirik

  I found several routers on newegg and they're in the $50-60 range, but I'm not sure if they'll handle the number of connections that are created when downloading torrents (100-300 seeds and around 50 peers). My roommate watches netflix movies, my brother and I download torrents, so my NETGEAR router ends up choking on the traffic and I have to restart it quite frequently. I've already posted a couple of questions on the topic and I've come to the conclusion that I need a new router. What are some routers that I should consider (my budget is in the $50 range)?

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• procmail issue - splitting delivery of one address based on destination domain

  - by warren

  I use procmail to handle some serverside mail processing. I am trying to setup one email address on a server that support multiple domains (in the example below, domain.net and domain.com). I want mail sent to [email protected] to go to bob and mail sent to [email protected] to go to sara. VERBOSE=off LOGFILE=/dev/null :0 * .domain.net bob :0 * .domain.com sara The above recipe seems to work quite well in that it catches incoming mail to domain.net and forwards it to bob. However, instead of forwarding mail to domain.com to sara, it creates a file in /home/user called sara. What am I doing wrong on this?

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• Hyper-V File Server Clustering - at my wit’s end

  - by René Kåbis

  I am at my wit’s end with File Server clustering under Hyper-V. I am hoping that someone might be able to help me figure out this Gordian Knot of a technology that seems to have dead ends (like forcing cluster VMs to use iSCSI drives where normally-attached VHDX drives could suffice) where logic and reason would normally provide a logical solution. My hardware: I will be running three servers (in the end), but right now everything is taking place on one server. One of the secondary servers will exist purely as a witness/quorum, and another slightly more powerful one will be acting as an emergency backup (with additional storage, just not redundant) to hold the secondary AD VM and the other halves of a set of clustered VMs: the SQL VM and the file system VM. Please note, these each are the depreciated nodes of a cluster, the main nodes will be on the most powerful first machine. My heavy lifter is a machine that also contains all of the truly redundant storage on the network. If this gives anyone the heebie-geebies, too bad. It has a 6TB (usable) RAID-10 array, and will (in the end) hold the primary nodes of both aforementioned clusters, but is right now holding all VMs. This is, right now: DC01, DC02, SQL01, SQL02, FS01 & FS02. Eventually, I will be adding additional VMs to handle Exchange, Sharepoint and Lync, but only to this main server (the secondary server won't be able to handle more than three or four VMs, so why burden it? The AD, SQL & FS VMs are the most critical for the business). If anyone is now saying, “wait, what about a SAN or a NAS for the file servers?”, well too bad. What exists on the main machine is what I have to deal with. I followed these instructions, but I seem to be unable to get things to work. In order to make the file server truly redundant, I cannot trust any one machine to hold the only data store on the network. Therefore, I have created a set of iSCSI drives on the VM-host of the main machine, and attached one to each file server VM. The end result is that I want my FS01 to sit on the heavy lifter, along with its iSCSI “drive”, and FS02 will sit on the secondary machine with its own iSCSI “drive” there as well. That is, neither iSCSI drive will end up sitting on the same machine as the other. As such, the clustered FS will utterly duplicate the contents of the iSCSI drives between each other, so that if one physical machine (or the FS VM) goes toes-up, the other has got a full copy of the data on its own iSCSI drive. My problem occurs when I try to apply the file server role within the failover cluster manager. Actually, it is even before that -- it occurs when adding the disks. Since I have added each disk preferentially to a specific VM (by limiting the initiator by DNS hostname, and by adding two-way CHAP authentication), this forces each VM to be in control of its own iSCSI disk. However, when I try to add the disks to the Disks section of Storage within Failover Cluster Manager, the entire process fails for a random disk of the pair. That is, one will get online, but the other will remain offline because it does not have the correct “owner node”. I mean, really -- WTF? Of course it doesn’t have the right owner node, both drives are showing the same node name!! I cannot seem to have one drive show up with one node name as owner, and the other drive show up with the other node name as owner. And because both drives are not “online”, I cannot create a pool to apply to a cluster role. Talk about getting stuck between a rock and a hard place! I’ve got more to add, but my work is closing for the day and I have to wrap things up. I will try to add more tomorrow morning when I get in. My main objective is to have a file server VM on each machine, the storage on each machine, but a transparent failover in case one physical machine fails. Essentially, a failover FS that doesn’t care which machine fails -- the storage contents are replicated equally on each machine. Am I even heading in the right direction?

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