Search Results

Search found 4461 results on 179 pages for 'availability groups'.

Page 144/179 | < Previous Page | 140 141 142 143 144 145 146 147 148 149 150 151  | Next Page >

• Sharing storage between servers

  - by El Yobo

  I have a PHP based web application which is currently only using one webserver but will shortly be scaling up to another. In most regards this is pretty straightforward, but the application also stores a lot of files on the filesystem. It seems that there are many approaches to sharing the files between the two servers, from the very simple to the reasonably complex. These are the options that I'm aware of Simple network storage NFS SMB/CIFS Clustered filesystems Lustre GFS/GFS2 GlusterFS Hadoop DFS MogileFS What I want is for a file uploaded via one webserver be immediately available if accessed through the other. The data is extremely important and absolutely cannot be lost, so whatever is implemented needs to a) never lose data and b) have very high availability (as good as, or better, than a local filesystem). It seems like the clustered filesystems will also provide faster data access than local storage (for large files) but that isn't of vita importance at the moment. What would you recommend? Do you have any suggestions to add or anything specifically to look out for with the above options? Any suggestions on how to manage backup of data on the clustered filesystems?

  Read the article

• Do complex JOINs cause high coupling and maintenance problems ?

  - by ashkan.kh.nazary

  Our project has ~40 tables with complex relations.A colleague believes in using long join queries which enforces me to learn about tables outside of my module but I think I should not concern about tables not directly related to my module and use data access functions (written by those responsible for other modules) when I need data from them. Let me clarify: I am responsible for the ContactVendor module which enables the customers to contact the vendor and start a conversation about some specific product. Products module has it's own complex tables and relations with functions that encapsulate details (for example i18n, activation, product availability etc ...). Now I need to show the product title of some product related to some conversation between the vendor and customers. I may either write a long query that retrieves the product info along with conversation stuff in one shot (which enforces me to learn about Product tables) OR I may pass the relevant product_id to the get_product_info(int) function. First approach is obviously demanding and introduces many bad practices and things I normally consider fault in programming. The problem with the second approach seems to be the countless mini queries these access functions cause and performance loss is a concern when a loop tries to fetch product titles for 100 products using functions that each perform a separate query. So I'm stuck between "don't code to the implementation, code to interface" and performance. What is the right way of doing things ? UPDATE: I'm specially concerned about possible future modifications to those tables outside of my module. What if the Products module decided to change the way they are doing things? or for some reason modify the schema? It means some other modules would break or malfunction until the change is integrated to them. The usual ripple effect problem.

  Read the article

• Thoughts on GoGrid vs EC2

  - by Jason

  I am currently hosting my SaaS application at GoGrid (Microsoft stack). Here's what I have: Database Server - physical box, 12 GB RAM, 2 X Quad Core CPU (2.13 GHz Xeon E5506) 2 Web / App servers - cloud servers, 2 GB RAM, 2 VCPUs 300 GB monthly bandwidth I am paying around $900 / month for this. My web / app servers are busting at the seams and need to be upgraded to 4 GB of RAM. I also need a firewall, and GoGrid just added this service for an additional $200. After the upgrade, I will be paying around $1,400. I started looking at Amazon EC2, specifically this config: Database server - "High Memory Double Extra Large Instance" - 34 GB RAM, 13 EC2 compute units 2 Web / App servers - "Large Instance" - 7.5 GB RAM, 4 EC2 compute units If I go with 1 year reserved instances, my upfront cost would be $4,500 and my monthly would be $700. This comes to $1,075 / month when amortized. Amazon also includes a firewall for free. Here are my questions: Do any of you have experience running a database (especially SQL Server) on an EC2 instance? How did it perform compared to a dedicated machine? One of my major concerns is with disk I/O. Amazon's description of a compute unit is fairly vague. Any ideas on how the CPU performance on the database servers would compare? I am hoping that the Amazon solution will provide significantly better performance than my current or even improved GoGrid setup. Having a virtual database server would also be nice in terms of availability. Right now I would be in serious trouble if I had any hardware issues. Thanks for any insight...

  Read the article

• Does complex JOINs causes high coupling and maintenance problems ?

  - by ashkan.kh.nazary

  Our project has ~40 tables with complex relations.A colleague believes in using long join queries which enforces me to learn about tables outside of my module but I think I should not concern about tables not directly related to my module and use data access functions (written by those responsible for other modules) when I need data from them. Let me clarify: I am responsible for the ContactVendor module which enables the customers to contact the vendor and start a conversation about some specific product. Products module has it's own complex tables and relations with functions that encapsulate details (for example i18n, activation, product availability etc ...). Now I need to show the product title of some product related to some conversation between the vendor and customers. I may either write a long query that retrieves the product info along with conversation stuff in one shot (which enforces me to learn about Product tables) OR I may pass the relevant product_id to the get_product_info(int) function. First approach is obviously demanding and introduces many bad practices and things I normally consider fault in programming. The problem with the second approach seems to be the countless mini queries these access functions cause and performance loss is a concern when a loop tries to fetch product titles for 100 products using functions that each perform a separate query. So I'm stuck between "don't code to the implementation, code to interface" and performance. What is the right way of doing things ? UPDATE: I'm specially concerned about possible future modifications to those tables outside of my module. What if the Products module decided to change the way they are doing things? or for some reason modify the schema? It means some other modules would break or malfunction until the change is integrated to them. The usual ripple effect problem.

  Read the article

• Should I close sockets from both ends?

  - by Roman

  I have the following problem. My client program monitor for availability of server in the local network (using Bonjour, but it does not rally mater). As soon as a server is "noticed" by the client application, the client tries to create a socket: Socket(serverIP,serverPort);. At some point the client can loose the server (Bonjour says that server is not visible in the network anymore). So, the client decide to close the socket, because it is not valid anymore. At some moment the server appears again. So, the client tries to create a new socket associated with this server. But! The server can refuse to create this socket since it (server) has already a socket associated with the client IP and client port. It happens because the socket was closed by the client, not by the server. Can it happen? And if it is the case, how this problem can be solved? Well, I understand that it is unlikely that the client will try to connect to the server from the same port (client port), since client selects its ports randomly. But it still can happen (just by chance). Right?

  Read the article

• How to create a platform ontop of CSLA? <-- if in case it make sense

  - by Peejay

  Hi all! here is the senario, i'm developing an application using csla 3.8 / c#.net, the application will have different modules. its like an ERP, it will have accounting, daily time record, recruitment etc as modules. Now the requirement is to check for common entities per module and build a "platform" (<- the boss calls it that way) from it. for example, DTR will have an entity "employee", Recruitment will have "Applicant" so one common entity that you can derive from both that can be put in the platform is "Person". "Person" will contain typical info like name, address, contact info etc. I know it sounds like OOP 101. the thing is, i dont know how i am to go about it. how i wish it was just a simple inheritance but the requirement is like to create an API of some sort to be used by the modules using CSLA. in csla you create smart objects right, inheriting from the base classes of csla like businessListbase, readonlylistbase etc. right? what if for example i created a businessbase Applicant class, it will have properties like salary demand, availability date etc. now for the personal info i will need the "Person" from the "platform" and implement it to the applicant class. so in summary i have several questions: how to create such platform? if such platform is possible, how will it be implemented on each module's entities? (im already inheriting from base clases of csla) if incase 1 and 2 are possible, does it have advantages on development and maintenace of the app? the reason why i'm asking #3 is because the way i see it, even if i am able to create a platform for that, i will be needing to define properties of the platform entity on my module entities so to have validation and all. im sorry if i'm typing nonesense i'm really confused. hope someone could enlighten me. thank you all!

  Read the article

• How to implement message queuing and handling in AWS with NServiceBus

  - by Pete Lunenfeld

  I am creating a new ASP MVC order application in the Amazon (AWS) cloud with the persistence layer at my local datacenter. I will be using the CQRS pattern. The goal of the project is high availability using Queue(s) to store and forward writes (commands/events) that can be picked up and handled asynchronously at my local datacenter. Then, ff the WAN or my local datacenter fails, my cloud MVC app can still take orders and just queue them up until processing can resume. My first thought was to use AWS SQS for the queuing and create my own queue consumer/dispatcher/handler in my own c# application to process the incoming messages/events. MVC (@ Amazon) -- Event/POCO -- SQS -- QueueReader (@ my datacenter) -- DB Then I found NServiceBus. NSB seems to handle lots of details very nicely: message handling, retries, error handling, etc. I hate to reinvent the wheel, and NServiceBus seems like a full featured and mature product that would be perfect for me. But on further research, it does NOT look like NServiceBus is really meant to be used over the WAN in physically separated environments (Cloud to my Datacenter). Google and SO don't really paint a good picture of using NServiceBus across the WAN like I need. How can I use NServiceBus across the WAN? Or is there a better solution to handle queuing and message handling between Amazon an my local datacenter?

  Read the article

• JQuery Post caused permission denied warning in IE 6 and IE 7

  - by kwokwai

  Hi all, I am using firefox 3 and IE 6, 7 to test if a simple php web page using JQuery Post to pass some data to and from another server web page. $(document).ready(function(){ $("#data\\[User\\]\\[name\\]").click(function(){ var usr=$("#data\\[User\\]\\[name\\]").val(); if(usr.length >= 4){ $("#username").append('<span id="loaderimg" name="loaderimg"><img align="absmiddle" src="loader.gif"/> Checking data availability,&nbsp;please wait.</span>'); var url = "http://mysite.com/site1/toavail/"+usr; $.post( url, function(data) {alert(data);}); }); }); //--> </script> <table border=0 width="100%"> <tr> <td>Username</td> <td> <div id="username"> <input type="text" name="data[User][name]" id="data[User][name]"> </div> </td> </tr> </table> In Firefox 3, the alert box showed empty message. In IE 6 and IE 7, I got an error message saying "Permssion denied"

  Read the article

• How do i sit 2 divs left and right of eachother

  - by s32ialx

  So what i am trying to acomplish is sitting <div id="box"> left of and <div id="box2"> right of inside the container of <div id="content"> <div id="content"> <div id="box1"> <h2>Company Information</h2> <img src="images/photo-about.jpg" alt="" width="177" height="117" class="aboutus-img" /> <p color="FF6600"> some content here </p> </div> <div id="clear"></div> <div id="box" style="width:350px;"> <h2>Availability</h2> <p> some more content here </p> </div> <div id="clear"></div> <div id="box2" style="width:350px;float:left;overflow: auto;"> <h2>Our Commitment</h2> <p> some content here </p> </div> </div>

  Read the article

• Is there a reason why SSIS significantly slows down after a few minutes?

  - by Mark

  I'm running a fairly substantial SSIS package against SQL 2008 - and I'm getting the same results both in my dev environment (Win7-x64 + SQL-x64-Developer) and the production environment (Server 2008 x64 + SQL Std x64). The symptom is that initial data loading screams at between 50K - 500K records per second, but after a few minutes the speed drops off dramatically and eventually crawls embarrasingly slowly. The database is in Simple recovery model, the target tables are empty, and all of the prerequisites for minimally logged bulk inserts are being met. The data flow is a simple load from a RAW input file to a schema-matched table (i.e. no complex transforms of data, no sorting, no lookups, no SCDs, etc.) The problem has the following qualities and resiliences: Problem persists no matter what the target table is. RAM usage is lowish (45%) - there's plenty of spare RAM available for SSIS buffers or SQL Server to use. Perfmon shows buffers are not spooling, disk response times are normal, disk availability is high. CPU usage is low (hovers around 25% shared between sqlserver.exe and DtsDebugHost.exe) Disk activity primarily on TempDB.mdf, but I/O is very low (< 600 Kb/s) OLE DB destination and SQL Server Destination both exhibit this problem. To sum it up, I expect either disk, CPU or RAM to be exhausted before the package slows down, but instead its as if the SSIS package is taking an afternoon nap. SQL server remains responsive to other queries, and I can't find any performance counters or logged events that betray the cause of the problem. I'll gratefully reward any reasonable answers / suggestions.

  Read the article

• SQL Structure of DB table with different types of columns

  - by Dmitry Dvornikov

  I have a problem with the optimization of the structure of the database. I'll try to explain it exactly. I create a project, where we can add different values??, but this values must have different types of the columns in the database (eg, int, double , varchar). What is the best way to store the different types of values ??in the database. In the project I'm using Propel 1.6. The point is availability to add value with 'int', 'varchar' and other columns types, to search the table was efficient. In total, I have two ideas. The first is to create a table of "value", which will have columns: "id ", "value_int", "value_double", "value_varchar", etc - with the corresponding column types. Depending on the type of values??, records will be saved with the value in the appropriate column (the rest will be NULL). The second solution is to create separate tables such as "value_int", "value_varchar" etc. There would be columns: "id", "value", which correspond to the relevant types of "value" (ie, such as int, varchar, etc). I must admit that I do not believe any of the above solutions, originally I was thinking about one table "value", where the column would be a "text" type - but this solution would probably be even worse. I would like to know your opinion on this topic, maybe something else would be better. Thanks in advance. EDIT: For example : We have three tables: USER: [table of users] * id * name FIELD: [table of profile fields - where the column 'type' is the type of field, eg int or varchar) * id * type * name VALUE : * id * User_id - ( FK user.id ) * Field_id - ( FK field.id ) * value So we have in each row an user in USER table, and the profile is stored in the VALUE table. Bit each profile field may have a different type (column 'type' in the FIELD table), and based on that I would want this value to add to the appropriate column of the appropriate type.

  Read the article

• Why represent shopping carts and order invoices differently in a domain model?

  - by Todd

  I've built some shopping cart systems in the past, but I always designed them such that the final order invoice is just a shopping cart that has been marked as "purchased". All the logic for adding/removing/changing items in a cart is also the logic for the order. All data is stored in the same tables in the database. But it seems this is not the proper way to design an e-commerce site.. Can someone explain the benefit of separating the shopping cart from invoices in the domain model? It seems to me this would lead to a lot of duplicated code, an extra set of tables in the database, and make it harder to maintain in the event the system need to start accommodating more complicated orders (like specifying selected options for an item which may or may not change the price/availability/shipping time of the order). I'm assuming I just haven't seen the light, as every book and other example I see seems to separate these two seemingly similar concerns -- but I can't find any explanation as to the benefit of doing such! It's also the case in the systems that I design that changes are often made after the initial order is confirmed. It's not uncommon for items to be removed, replaced, or added afterwards (but prior to fulfillment).

  Read the article

• web service slowdown

  - by user238591

  Hi, I have a web service slowdown. My (web) service is in gsoap & managed C++. It's not IIS/apache hosted, but speaks xml. My client is in .NET The service computation time is light (<0.1s to prepare reply). I expect the service to be smooth, fast and have good availability. I have about 100 clients, response time is 1s mandatory. Clients have about 1 request per minute. Clients are checking web service presence by tcp open port test. So, to avoid possible congestion, I turned gSoap KeepAlive to false. Until there everything runs fine : I bearly see connections in TCPView (sysinternals) New special synchronisation program now calls the service in a loop. It's higher load but everything is processed in less 30 seconds. With sysinternals TCPView, I see that about 1 thousands connections are in TIME_WAIT. They slowdown the service and It takes seconds for the service to reply, now. Could it be that I need to reset the SoapHttpClientProtocol connection ? Someone has TIME_WAIT ghosts with a web service call in a loop ?

  Read the article

• Advice: Python Framework Server/Worker Queue management (not Website)

  - by Muppet Geoff

  I am looking for some advice/opinions of which Python Framework to use in an implementation of multiple 'Worker' PCs co-ordinated from a central Queue Manager. For completeness, the 'Worker' PCs will be running Audio Conversion routines (which I do not need advice on, and have standalone code that works). The Audio conversion takes a long time, and I need to co-ordinate an arbitrary number of the 'Workers' from a central location, handing them conversion tasks (such as where to get the source files, or where to ask for the job configuration) with them reporting back some additional info, such as the runtime of the converted audio etc. At present, I have a script that makes a webservice call to get the 'configuration' for a conversion task, based on source files located on the worker already (we manually copy the source files to the worker, and that triggers a conversion routine). I want to change this, so that we can distribute conversion tasks ("Oy you, process this: xxx") based on availability, and in an ideal world, based on pending tasks too. There is a chance that Workers can go offline mid-conversion (but this is not likely). All the workers are Windows based, the co-ordinator can be WIndows or Linux. I have (in my initial searches) come across the following - and I know that some are cross-dependent: Celery (with RabbitMQ) Twisted Django Using a framework, rather than home-brewing, seems to make more sense to me right now. I have a limited timeframe in which to develop this functional extension. An additional consideration would be using a Framework that is compatible with PyQT/PySide so that I can write a simple UI to display Queue status etc. I appreciate that the specifics above are a little vague, and I hope that someone can offer me a pointer or two. Again: I am looking for general advice on which Python framework to investigate further, for developing a Server/Worker 'Queue management' solution, for non-web activities (this is why DJango didn't seem the right fit).

  Read the article

• AJAX help needed

  - by tharindu

  Hi guys.. i have problem in ajax.. im new comer for ajax...:) <script type="text/javascript"> $(document).ready(function() { $("#bcode").focus(); //prevents autocomplete in some browsers $("#bcode").attr('autocomplete', 'off').keyup(function(event) { var name = $("#bcode").val(); $("#status").empty(); if(name.length > 17 ) { selectAll(); $("#status").html('<img align="absmiddle" src="loading.gif" /> Checking availability...').show(); $.ajax({ type: "POST", url: "namecheck.php", data: "bcode="+ name, success: function(msg) { $("#status").html(msg).show(); } }); } else { $("#status").html('').addClass('err').show(); } }); }); //--> </script> i got text box value 'bcode' using '$_POST['bcode']' <input name="bcode" type="text" class="bcode" id="bcode" maxlength="18"; /> also i have menu/list in that form <select name="pallete" class="list_box" id="select"> <option value="P0" selected> </option> <option value="P1">P1</option> <option value="P2">P2</option> <option value="P3">P3</option> <option value="P4">P4</option> <option value="P5">P5</option> </select> How i can access selected item from php file by using '$_POST['pallete']' please help me. Thanks in advance..

  Read the article

• Fastest reliable way for Clojure (Java) and Ruby apps to communicate

  - by jkndrkn

  Hi There, We have cloud-hosted (RackSpace cloud) Ruby and Java apps that will interact as follows: Ruby app sends a request to Java app. Request consists of map structure containing strings, integers, other maps, and lists (analogous to JSON). Java app analyzes data and sends reply to Ruby App. We are interested in evaluating both messaging formats (JSON, Buffer Protocols, Thrift, etc.) as well as message transmission channels/techniques (sockets, message queues, RPC, REST, SOAP, etc.) Our criteria: Short round-trip time. Low round-trip-time standard deviation. (We understand that garbage collection pauses and network usage spikes can affect this value). High availability. Scalability (we may want to have multiple instances of Ruby and Java app exchanging point-to-point messages in the future). Ease of debugging and profiling. Good documentation and community support. Bonus points for Clojure support. What combination of message format and transmission method would you recommend? Why? I've gathered here some materials we have already collected for review: Comparison of various java serialization options Comparison of Thrift and Protocol Buffers (old) Comparison of various data interchange formats Comparison of Thrift and Protocol Buffers Fallacies of Protocol Buffers RPC features Discussion of RPC in the context of AMQP (Message-Queueing) Comparison of RPC and message-passing in distributed systems (pdf) Criticism of RPC from perspective of message-passing fan Overview of Avro from Ruby programmer perspective

  Read the article

• Getting hover text with selenium in java

  - by BinaryEmpire

  I am trying to figure out how to get the product availability text from a page like http://www.walmart.com/browse/TV-Video/TVs/_/N-96v3? (once a store has been selected) I selected 76574 as my zipcode and went to the "In My Store" tab The code I have now is WebElement hoverElement = driver.findElement(By.xpath(".//*[@id='Body_15992428']/span")); WebElement hidden = driver.findElement(By.xpath(".//*[@id='slapInfo_NoVariant_15992428']/div")); Actions builder = new Actions(driver); builder.clickAndHold(hoverElement).build().perform(); System.out.println(hidden.getText()); **Edit: I tried profile.setEnableNativeEvents(false); and the text is now displayed in the automated browser window. I still cannot get to the text I want though. It does not throw an exception, only displays nothing because the driver thinks its still hidden. Any one know how to fix this? I keep getting Exception in thread "main" org.openqa.selenium.InvalidElementStateException: Cannot perform native interaction: Could not load native events component. Even after I do profile.setEnableNativeEvents(true); Are there any other ways I can get the hidden text, or what am I doing wrong here? Additionally while I was inspecting the code with firebug, I saw that there is this code <script type="text/javascript"> WALMART.$(document).ready(function(){ WALMART.$('#Body_15992428').hover(function(){ WALMART.$('#SeeStoreAvailBubble').wmBubble('update',WALMART.$('#bubbleMsgUpdate_15992428').html()); }); }); </script> I dont really know how to do things directly with javascript but is there is any way of getting the message text directly from that with a javascript executor?

  Read the article

• Safe way for getting/finding a vertex in a graph with custom properties -> good programming practice

  - by Shadow

  Hi, I am writing a Graph-class using boost-graph-library. I use custom vertex and edge properties and a map to store/find the vertices/edges for a given property. I'm satisfied with how it works, so far. However, I have a small problem, where I'm not sure how to solve it "nicely". The class provides a method Vertex getVertex(Vertexproperties v_prop) and a method bool hasVertex(Vertexproperties v_prop) The question now is, would you judge this as good programming practice in C++? My opinion is, that I have first to check if something is available before I can get it. So, before getting a vertex with a desired property, one has to check if hasVertex() would return true for those properties. However, I would like to make getVertex() a bit more robust. ATM it will segfault when one would directly call getVertex() without prior checking if the graph has a corresponding vertex. A first idea was to return a NULL-pointer or a pointer that points past the last stored vertex. For the latter, I haven't found out how to do this. But even with this "robust" version, one would have to check for correctness after getting a vertex or one would also run into a SegFault when dereferencing that vertex-pointer for example. Therefore I am wondering if it is "ok" to let getVertex() SegFault if one does not check for availability beforehand?

  Read the article

• How would you structure your workflow for a web application ?

  - by cx42net

  Hi ! When designing a web application (or something else), it's good to have a workflow, and it's better to have a well ordered one. Starting with this idea in mind, I'd like to know what is your process from having an idea to maintain this great working project. For me actually, the process is the following one : Having the idea Checking this project already exists, and how it works Describing on a paper its functionalities finding a good and adequate name for this (and checking the domain availability with WHOISMyProject) Making a quick layout of the project on a paper Designing the project (via TheGimp, Photoshop, etc) Making a complete mockup of each pages Developing a prototype of the client-side application (with false datas) Developing the server side Testing Making the documentation/help/faq Releasing the project Maintaining it. Would you change the order of some points ? add/remove some ? I would please to know how you do that. I'm looking to set up a perfect workflow in order to make my project become real in the best way possible. Thank you for your opinion !

  Read the article

• iPhone app developed with SDK 4.2, requires backward compatibility with iOS 3.1.3 .. easy way?

  - by mrd3650

  I have built an iPhone app with SDK 4.2 however I know also want to make it compatible with iOS 3.1.3. First step was to set the Deployment Target to 3.1.3. It runs fine on the 3.2 Simulator but the app crashes at times since I'm using some methods which are not available in this early SDK. So my qestion is, is there a straight forward way to locate the offending methods/classes I'm using in my project which are not available in 3.1.3 ? (without manually going through each method call and consult with the docs for the SDK availability?) Thanks. UPDATE: I have executed the app on 3.1.3 and attempted to manually test each execution path with the hope of locating all exceptions. This was completed with some level of success. However, what if the application is huge? and there are lots of execution paths? There must be some tool for this scenario. Any thoughts are much appreciated.

  Read the article

• Handling bounced email when using a postfix smarthost

  - by Mark Rose

  I'm running a high availability cluster, and so far, most things work great. I have two external machines that act as outgoing mail hosts (smarthosts). The internal hosts are configured to relay all email through these two external facing hosts. My smarthosts' main.cf looks like this: myhostname = lb1.example.com alias_maps = hash:/etc/aliases alias_database = hash:/etc/aliases mydestination = lb1.example.com, localhost relayhost = mynetworks = 127.0.0.0/8 10.1.248.0/24 My internal hosts' main.cf looks like this: mynetworks = 127.0.0.0/8 myhostname = web1.example.com mydestination = $myhostname, localhost.$mydomain, localhost relayhost = [10.1.248.3] smtp_fallback_relay = [10.1.248.2] lb1's internal IP is 10.1.248.2, and lb2's internal IP is 10.1.248.3. On the external hosts, email for root and www-data is forwarded to [email protected] with /etc/aliases. One advantage to using the smarthost setup is that spam filters and the like can connect back to the sending sending server. All email is sent fine, and headers look like this: Received: from lb2.example.com ([198.51.100.3]) by mx.google.com with ESMTP id y17si1571259icb.76.2011.01.13.18.20.32; Thu, 13 Jan 2011 18:20:32 -0800 (PST) Received-SPF: neutral (google.com: 198.51.100.3 is neither permitted nor denied by best guess record for domain of [email protected]) client-ip=198.51.100.3; Received: from db1.example.com (unknown [10.1.248.20]) by lb2.example.com (Postfix) with ESMTP id D364823C0BE for <[email protected]>; Thu, 13 Jan 2011 21:20:31 -0500 (EST) Received: by db1.example.com (Postfix) id C9FA7760D6A; Thu, 13 Jan 2011 21:20:31 -0500 (EST) Delivered-To: www-data@localhost Received: by db1.example.com (Postfix, from userid 0) id C1632760D6C; Thu, 13 Jan 2011 21:20:31 -0500 (EST) The problem is bounced/reject email. The external machine tries to forward the email back to the internal machine, e.g. www-data on web1 sending an email that bounces (such as a user signing up with a bad email address). An additional complication is using Google mail for the main example.com domain. In lieu of specifying every internal host in the external hosts' mydestination, is there a better way of setting things up, keeping in mind I can't adjust touch the mx for example.com?

  Read the article

• PowerDNS CNAME with multiple A records produces unexpected results

  - by bwight

  This problem from what i can tell is isolated to PowerDNS. The servers are running two packages pdns-static-3.0.1-1.i386.rpm and pdns-recursor-3.3-1.i386.rpm on the most recent version of Amazon Linux. The amazon ec2 loadbalancers are assigned a CNAME with multiple hosts. Below is an example of the actual behavior. Notice how the hosts are always in the same order. [root@localhost ~]# host cache.domain.com cache.domain.com is an alias for xxxxx.us-east-1.elb.amazonaws.com. xxxxx.us-east-1.elb.amazonaws.com has address aaa.aaa.aaa.aaa xxxxx.us-east-1.elb.amazonaws.com has address bbb.bbb.bbb.bbb [root@localhost ~]# host cache.domain.com cache.domain.com is an alias for xxxxx.us-east-1.elb.amazonaws.com. xxxxx.us-east-1.elb.amazonaws.com has address aaa.aaa.aaa.aaa xxxxx.us-east-1.elb.amazonaws.com has address bbb.bbb.bbb.bbb [root@localhost ~]# host cache.domain.com cache.domain.com is an alias for xxxxx.us-east-1.elb.amazonaws.com. xxxxx.us-east-1.elb.amazonaws.com has address aaa.aaa.aaa.aaa xxxxx.us-east-1.elb.amazonaws.com has address bbb.bbb.bbb.bbb Expected behavior is round robin for the hosts [root@localhost ~]# host cache.domain.com cache.domain.com is an alias for xxxxx.us-east-1.elb.amazonaws.com. xxxxx.us-east-1.elb.amazonaws.com has address aaa.aaa.aaa.aaa xxxxx.us-east-1.elb.amazonaws.com has address bbb.bbb.bbb.bbb [root@localhost ~]# host cache.domain.com cache.domain.com is an alias for xxxxx.us-east-1.elb.amazonaws.com. xxxxx.us-east-1.elb.amazonaws.com has address bbb.bbb.bbb.bbb xxxxx.us-east-1.elb.amazonaws.com has address aaa.aaa.aaa.aaa [root@localhost ~]# host cache.domain.com cache.domain.com is an alias for xxxxx.us-east-1.elb.amazonaws.com. xxxxx.us-east-1.elb.amazonaws.com has address aaa.aaa.aaa.aaa xxxxx.us-east-1.elb.amazonaws.com has address bbb.bbb.bbb.bbb The addresses eventually do swap but it seems to be on a 30 minute cache timer changing the TTL of the record doesn't appear to affect anything. It appears as though the resolver has a cache of the response. This adversely affects my application because all of the load is only being sent to one of the loadbalancers (Availability Zones) so if I have servers in two zones then only one zone is under load at a time. Do you know how I can fix this so that each time the host is resolved the order of the addresses is alternating.

  Read the article

• Building an SSL server farm

  - by dan

  I'm interested in building the the architecture in the article referenced below. I currently have a modestly-priced layer-4 load balancer and my application servers are the SSL endpoints. I want to put an SSL server farm in between my load balancer and my app servers. Then I will put another inexpensive load balancer between the SSL farm and my app servers, to do layer-7 routing. My web application has a fairly high amount of consumer traffic, that 6 servers can handle at about 50% capacity. Additionally, I have infrastructure traffic that is several orders of magnitude heavier than my consumer traffic. This is data coming in from all over the world that must integrate with my web application in real time. In total I have 18 app servers to handle all the traffic, plus 6 database servers. I will be adding 6 more app servers over the next 2 weeks and another 6 the 2 weeks after that. Conservatively, I estimate I will need to scale to 120 servers by the end of the year. My motivation right now is to separate the consumer traffic from the infrastructure traffic. The consumer traffic is higher priority than the infrastructure traffic and I cannot allow a stampede on the infrastructure side to take down my consumer-facing servers. Having a website that is always up is the top priority. However if there is a failure in one of the consumer app servers, I want to route that traffic to the servers designated for infrastructure traffic. The complication is that all the traffic is addressed using the same hostname and is nearly 100% https. The only way in my case to distinguish infrastructure from consumer traffic is by URL (poor architecture I inherited), so I need a layer 7 load balancer to be able to route. However for that to work I need either a fancy hardware-based SSL terminator or an SSL server farm as described above. Because my user base is rapidly scaling, I worry that if I go down the hardware path it will become very expensive very fast, especially since I will need 4 of everything for high availability (2 identical setups in 2 facilities). Meanwhile, the above diagram seems very flexible and more horizontally scalable. Has anyone built this before? Are there pre-built configurations? What considerations should I make and what software should I use (I've heard of people using apache with mod-ssl, nginx, and stunnel)? Also, when does it make sense to buy an expensive load balancer vs building an SSL server farm? http://1wt.eu/articles/2006_lb/index_05.html

  Read the article

• OS X server large scale storage and backup

  - by user135217

  I really hope this question doesn't come across as trolling or asking for buying advice. It's not intended. I've just started working for a small ad agency (40 employees). I actually quit being a system administrator a few years ago (too stressful!), but the company we're currently outsourcing our IT stuff to is doing such a bad job that I've felt compelled to get involved and do what I can to improve things. At the moment, all the company's data is stored on an 8TB external firewire drive attached to a Mac Mini running OS X Server 10.6, which provides filesharing (using AFP) for the whole company. There is a single backup drive, which is actually a caddy containing two 3TB hard drives arranged in RAID 0 (arrggghhhh!), which someone brings in as and when and copies over all the data using Carbon Copy Cloner. That's the entirety of the infrastructure, and the whole backup and restore strategy. I've been having sleepless nights. I've just started augmenting the backup process with FreeBSD, ZFS, sparse bundles and snapshot sends to get everything offsite. I think this is a workable behind the scenes solution, but for people's day to day use I'm struggling. Given the quantity and importance of the data, I think we should really be looking towards enterprise level storage solutions, high availability and so on, but the whole company is all Mac all the time, and I cannot find equipment that will do what we need. No more Xserve; no rack storage; no large scale storage at all apart from that Pegasus R6 that doesn't seem all that great; the Mac Pro has fibre channel, but it's not a real server and it's ludicrously expensive; Xsan looks like it's on the way out; things like heartbeatd and failoverd have apparently been removed from Lion Server; the new Mac Mini only has thunderbolt which severely limits our choices; the list goes on and on. I'm really, really not trying to troll here. I love Macs, but I just genuinely don't know where I'm supposed to look for server stuff. I have considered Linux or FreeBSD and netatalk for serving files with all the server-y goodness those OSes bring, but some the things I've read make me wonder if it's really the way to go. Also, in my own (admittedly quite cursory) experiments with it, I've struggled to get decent transfer speeds. I guess there's also the possibility of switching everyone off AFP and making them use SMB or NFS, but I understand that this can cause big problems with resource forks and file locks. I figure there must be plenty of all Mac companies out there. If you're the sysadmin at one, what do you use? Any suggestions very gratefully received.

  Read the article

• IT merger - self-sufficient site with domain controller VS thin clients outpost with access to termi

  - by imagodei

  SITUATION: A larger company acquires a smaller one. IT infrastructure has to be merged. There are no immediate plans to change the current size or role of the smaller company - the offices and production remain. It has a Win 2003 SBS domain server, Win 2000 file server, linux server for SVN and internal Wikipedia, 2 or 3 production machines, LTO backup solution. The servers are approx. 5 years old. Cisco network equippment (switches, wireless, ASA). Mail solution is a hosted Exchange. There are approx. 35 desktops and laptops in the company. IT infrastructure unification: There are 2 IT merging proposals. 1.) Replacing old servers, installing Win Server 2008 domain controller, and setting up either subdomain or domain trust to a larger company. File server and other servers remain local and synchronization should be set up to a centralized location in larger company. Similary with the backup - it remains local and if needed it should be replicated to a centralized location. Licensing is managed by smaller company. 2.) All servers are moved to a centralized location in larger company. As many desktop machines as possible are replaced by thin clients. The actual machines are virtualized and hosted by Terminal server at the same central location. Citrix solutions will be used. Only router and site-2-site VPN connection remain at the smaller company. Backup internet line to insure near 100% availability is needed. Licensing is mainly managed by larger company. Only specialized software for PCs that will not be virtualized is managed by smaller company. I'd like to ask you to discuss both solutions a bit. In your opinion, which is better from the operational point of view? Which is more reliable, cheaper in the long run? Easier to manage from the system administrator's point of view? Easier on the budget and easier to maintain from IT department's point of view? Does anybody have any experience with the second option and how does it perform in production environment? Pros and cons of both? Your input will be of great significance to me. Thank you very much!

  Read the article

< Previous Page | 140 141 142 143 144 145 146 147 148 149 150 151  | Next Page >