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  • Putting our OLTP and OLAP services on the same cluster

    - by Dynamo
    We're currently in a bit of a debate about what to do with our scattered SQL environment. We are setting up a cluster for our data warehouses for sure and are now in the process of deciding if our OLTP databases should go on the same one. The cluster will be active/active with database services running on one node and reporting and analytical services on the other node. From a technical standpoint I don't see an issue here. With the services being run on different nodes they shouldn't compete too heavily for resources. The only physical resource that may be an issue would be the shared disk space. Our environment is also quite small. Our biggest OLAP database at the moment is only about 40GB and our OLTP are all under 10GB. I see a potential political issue here as different groups are involved but I'm just strictly wondering if there would be any major technical issues that could arise from this setup.

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  • Hyper V cluster - one VM won't migrate

    - by Chris W
    We have a Failover Cluster built up on 6 blades, each running Hyper V. Each box is running Server 2008 R2. We've got a number of VMs running that all have the same basic config: VHD stored on a cluster shared volume. 2 virtual NICs (1 for LAN connection and 1 for SAN connection). All of our VMs will happily migrate between any other blade apart from one single VM which is running fine on it's current blade but will not migrate to any other location. What could be the cause of it or where should I look to get a detailed error message as I can't seem to find much information logged in any of the logs. Edit: I know the usual culprit is mis-matching resource names. We've already been there with the NICs named differently on some of the blades. As far as we can tell now everything looks to be identical on each bit of metal.

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  • Can i use a Windows 2008 r2 Cluster for file redundancy

    - by JERiv
    I'm researching a sever clustering architecture as a redundancy and backup solution for a client, and something that isn't made clear is whether or not i can use server clustering to replace a file server with backup solution. Forgive my Elementary understanding of server clustering but supposing: 2 Sites (NJ, CA) Identical Servers at each site setup as a Remote Site Cluster nodes with Windows Enterprise server 2008 r2 Services: File, Terminal, AD, and maybe DNS Will the following will be true: Files (including data drives) will be synced between the two servers eliminating the need for third party backup/mirroring software to sync/backup files. Also supposing i use roaming profiles w/ folder redirection; How will client computer in the WAN access their data through the cluster (i.e. will they automatically choose the best route)

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  • kSOAP2 and SOAPAction on Android

    - by Matze
    Hi everyone, I am trying to access a Webservice with kSOAP2 on an Android Phone. I think the connection is being established, but the server won't answer my request since I'm not providing a SOAP Action Header which seems to be required in SOAP Version 1.1(please correct me if I'm wrong here) which I have to use since the server does not support Version 1.2 . The concrete Faultcode which is returning in the request looks like this: faultactor null faultcode "S:Server" (id=830064966432) faultstring "String index out of range: -11" (id=830064966736) The errorcode which is generated on the server (I'm running it on a localhost) looks like this: 4.05.2010 20:20:29 com.sun.xml.internal.ws.transport.http.HttpAdapter fixQuotesAroundSoapAction WARNUNG: Received WS-I BP non-conformant Unquoted SoapAction HTTP header: http://server.contextlayer.bscwi.de/createContext 24.05.2010 20:20:29 com.sun.xml.internal.ws.server.sei.EndpointMethodHandler invoke SCHWERWIEGEND: String index out of range: -11 java.lang.StringIndexOutOfBoundsException: String index out of range: -11 at java.lang.String.substring(Unknown Source) at de.bscwi.contextlayer.xml.XmlValidator.isValid(XmlValidator.java:41) at de.bscwi.contextlayer.server.ContextWS.createContext(ContextWS.java:45) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at com.sun.xml.internal.ws.api.server.InstanceResolver$1.invoke(Unknown Source) at com.sun.xml.internal.ws.server.InvokerTube$2.invoke(Unknown Source) at com.sun.xml.internal.ws.server.sei.EndpointMethodHandler.invoke(Unknown Source) at com.sun.xml.internal.ws.server.sei.SEIInvokerTube.processRequest(Unknown Source) at com.sun.xml.internal.ws.api.pipe.Fiber.__doRun(Unknown Source) at com.sun.xml.internal.ws.api.pipe.Fiber._doRun(Unknown Source) at com.sun.xml.internal.ws.api.pipe.Fiber.doRun(Unknown Source) at com.sun.xml.internal.ws.api.pipe.Fiber.runSync(Unknown Source) at com.sun.xml.internal.ws.server.WSEndpointImpl$2.process(Unknown Source) at com.sun.xml.internal.ws.transport.http.HttpAdapter$HttpToolkit.handle(Unknown Source) at com.sun.xml.internal.ws.transport.http.HttpAdapter.handle(Unknown Source) at com.sun.xml.internal.ws.transport.http.server.WSHttpHandler.handleExchange(Unknown Source) at com.sun.xml.internal.ws.transport.http.server.WSHttpHandler.handle(Unknown Source) at com.sun.net.httpserver.Filter$Chain.doFilter(Unknown Source) at sun.net.httpserver.AuthFilter.doFilter(Unknown Source) at com.sun.net.httpserver.Filter$Chain.doFilter(Unknown Source) at sun.net.httpserver.ServerImpl$Exchange$LinkHandler.handle(Unknown Source) at com.sun.net.httpserver.Filter$Chain.doFilter(Unknown Source) at sun.net.httpserver.ServerImpl$Exchange.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) The relevant part of the WSDL (at least that's what I'm thinking) looks like this: <operation name="createContext"> <soap:operation soapAction=""/> - <input> <soap:body use="literal" namespace="http://server.contextlayer.bscwi.de/"/> </input> - <output> <soap:body use="literal" namespace="http://server.contextlayer.bscwi.de/"/> </output> </operation> In my code I'm adding a Header, but it seems like I'm doing it wrong: private static final String SOAP_ACTION = ""; //... SoapSerializationEnvelope soapEnvelope = new SoapSerializationEnvelope (SoapEnvelope.VER11); soapEnvelope.setOutputSoapObject(Request); AndroidHttpTransport aht = new AndroidHttpTransport (URL); //... aht.call(SOAP_ACTION, soapEnvelope); SoapPrimitive resultString = (SoapPrimitive) soapEnvelope.getResponse(); Any advice would be great since I'm running out of ideas.. Thanks folks!

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  • Why so Long time span in creating Session Factory?

    - by vijay.shad
    Hi My project is web application running in the tomcat container. This application is a spring framework based hibernate application. The problem with this is it takes a lot of time when creates session factory. here is the logs 2010-04-15 23:05:28,053 DEBUG [SessionFactoryImpl] Session factory constructed with filter configurations : {} 2010-04-15 23:05:28,053 DEBUG [SessionFactoryImpl] instantiating session factory with properties: {java.vendor=Sun Microsystems Inc., sun.java.launcher=SUN_STANDARD, catalina.base=/usr/local/InstalledPrograms/apache-tomcat-6.0.20, sun.management.compiler=HotSpot Tiered Compilers, catalina.useNaming=true, os.name=Linux, sun.boot.class.path=/usr/java/jdk1.6.0_17/jre/lib/resources.jar:/usr/java/jdk1.6.0_17/jre/lib/rt.jar:/usr/java/jdk1.6.0_17/jre/lib/sunrsasign.jar:/usr/java/jdk1.6.0_17/jre/lib/jsse.jar:/usr/java/jdk1.6.0_17/jre/lib/jce.jar:/usr/java/jdk1.6.0_17/jre/lib/charsets.jar:/usr/java/jdk1.6.0_17/jre/classes, java.util.logging.config.file=/usr/local/InstalledPrograms/apache-tomcat-6.0.20/conf/logging.properties, java.vm.specification.vendor=Sun Microsystems Inc., hibernate.generate_statistics=true, java.runtime.version=1.6.0_17-b04, hibernate.cache.provider_class=org.hibernate.cache.EhCacheProvider, user.name=root, shared.loader=, tomcat.util.buf.StringCache.byte.enabled=true, hibernate.connection.release_mode=auto, user.language=en, java.naming.factory.initial=org.apache.naming.java.javaURLContextFactory, sun.boot.library.path=/usr/java/jdk1.6.0_17/jre/lib/i386, java.version=1.6.0_17, java.util.logging.manager=org.apache.juli.ClassLoaderLogManager, user.timezone=Canada/Pacific, sun.arch.data.model=32, java.endorsed.dirs=/usr/local/InstalledPrograms/apache-tomcat-6.0.20/endorsed, sun.cpu.isalist=, sun.jnu.encoding=UTF-8, file.encoding.pkg=sun.io, package.access=sun.,org.apache.catalina.,org.apache.coyote.,org.apache.tomcat.,org.apache.jasper.,sun.beans., file.separator=/, java.specification.name=Java Platform API Specification, java.class.version=50.0, user.country=US, java.home=/usr/java/jdk1.6.0_17/jre, java.vm.info=mixed mode, os.version=2.6.18-128.el5, path.separator=:, java.vm.version=14.3-b01, hibernate.jdbc.batch_size=25, java.awt.printerjob=sun.print.PSPrinterJob, sun.io.unicode.encoding=UnicodeLittle, package.definition=sun.,java.,org.apache.catalina.,org.apache.coyote.,org.apache.tomcat.,org.apache.jasper., java.naming.factory.url.pkgs=org.apache.naming, sun.rmi.dgc.client.gcInterval=3600000, user.home=/root, java.specification.vendor=Sun Microsystems Inc., java.library.path=/usr/java/jdk1.6.0_17/jre/lib/i386/server:/usr/java/jdk1.6.0_17/jre/lib/i386:/usr/java/jdk1.6.0_17/jre/../lib/i386:/usr/java/packages/lib/i386:/lib:/usr/lib, java.vendor.url=http://java.sun.com/, java.vm.vendor=Sun Microsystems Inc., hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect, sun.rmi.dgc.server.gcInterval=3600000, common.loader=${catalina.home}/lib,${catalina.home}/lib/*.jar, java.runtime.name=Java(TM) SE Runtime Environment, java.class.path=:/usr/local/InstalledPrograms/apache-tomcat-6.0.20/bin/bootstrap.jar, hibernate.bytecode.use_reflection_optimizer=false, java.vm.specification.name=Java Virtual Machine Specification, java.vm.specification.version=1.0, catalina.home=/usr/local/InstalledPrograms/apache-tomcat-6.0.20, sun.cpu.endian=little, sun.os.patch.level=unknown, hibernate.cache.use_query_cache=true, hibernate.connection.provider_class=org.springframework.orm.hibernate3.LocalDataSourceConnectionProvider, java.io.tmpdir=/usr/local/InstalledPrograms/apache-tomcat-6.0.20/temp, java.vendor.url.bug=http://java.sun.com/cgi-bin/bugreport.cgi, server.loader=, os.arch=i386, java.awt.graphicsenv=sun.awt.X11GraphicsEnvironment, java.ext.dirs=/usr/java/jdk1.6.0_17/jre/lib/ext:/usr/java/packages/lib/ext, user.dir=/, line.separator=, java.vm.name=Java HotSpot(TM) Server VM, hibernate.cache.use_second_level_cache=true, file.encoding=UTF-8, java.specification.version=1.6, hibernate.show_sql=true} 2010-04-15 23:08:53,516 DEBUG [AbstractEntityPersister] Static SQL for entity: com.vsd.model.Order There you can see the time delay of more than 3 mins in executing these processes. My database is mysql and database server is running on the local machine only. The container environment is Centos Linux system. I am clueless about why it takes that much of time in executing these process, But when i do the same task from under eclipse it does not take that much of time. Development environment is Windows.

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  • OCFS2 Now Certified for E-Business Suite Release 12 Application Tiers

    - by sergio.leunissen
    Steven Chan writes that OCFS2 is now certified for use as a clustered filesystem for sharing files between all of your E-Business Suite application tier servers.  OCFS2 (Oracle Cluster File System 2) is a free, open source, general-purpose, extent-based clustered file system which Oracle developed and contributed to the Linux community.  It was accepted into Linux kernel 2.6.16.OCFS2 is included in Oracle Enterprise Linux (OEL) and supported under Unbreakable Linux support.

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  • An Interview with Wim Coekaerts

    - by [email protected]
    It isn't everyday you get to hear an interview with an SVP at Oracle, nor do you often get glimpses into the future of Oracle products. However - in this interview you get both. listen to Wim talk about Sun Rays, VDI and what Virtual Iron might mean to the mix of products coming...Enjoy

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  • Focus On Systems Admins and Developers

    - by rickramsey
    Even if you're not going to Oracle Open World, you might find it interesting to hear what the different technology groups at Oracle are going to be talking about. And if you are going, here's your Systems schedule: Note: all links go to PDF files. Focus On: Oracle Linux Focus On: Oracle Solaris Focus On: Oracle Solaris Cluster Focus On: Oracle Solaris Studio Focus On: Desktop Virtualization Focus On: Oracle VM Server Virtualization Focus On: SPARC Servers Focus On: Storage Focus On: SPARC Supercluster - Rick Website Newsletter Facebook Twitter

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  • Memory Leak Issue in Weblogic, SUN, Apache and Oracle classes Options

    - by Amit
    Hi All, Please find below the description of memory leaks issues. Statistics show major growth in the perm area (static classes). Flows were ran for 8 hours , Heap dump was taken after 2 hours and at the end. A growth in Perm area was identified Statistics show from our last run 240MB growth in 6 hour,40mb growth every hour 2GB heap –can hold ¾ days ,heap will be full in ¾ days Heap dump show –growth in area as mentioned below JMS connection/session Area Apache org.apache.xml.dtm.DTM[] org.apache.xml.dtm.ref.ExpandedNameTable$ExtendedType org.jdom.AttributeList org.jdom.Content[] org.jdom.ContentList org.jdom.Element SUN * ConstantPoolCacheKlass * ConstantPoolKlass * ConstMethodKlass * MethodDataKlass * MethodKlass * SymbolKlass byte[] char[] com.sun.org.apache.xml.internal.dtm.DTM[] com.sun.org.apache.xml.internal.dtm.ref.ExtendedType java.beans.PropertyDescriptor java.lang.Class java.lang.Long java.lang.ref.WeakReference java.lang.ref.SoftReference java.lang.String java.text.Format[] java.util.concurrent.ConcurrentHashMap$Segment java.util.LinkedList$Entry Weblogic com.bea.console.cvo.ConsoleValueObject$PropertyInfo com.bea.jsptools.tree.TreeNode com.bea.netuix.servlets.controls.content.StrutsContent com.bea.netuix.servlets.controls.layout.FlowLayout com.bea.netuix.servlets.controls.layout.GridLayout com.bea.netuix.servlets.controls.layout.Placeholder com.bea.netuix.servlets.controls.page.Book com.bea.netuix.servlets.controls.window.Window[] com.bea.netuix.servlets.controls.window.WindowMode javax.management.modelmbean.ModelMBeanAttributeInfo weblogic.apache.xerces.parsers.SecurityConfiguration weblogic.apache.xerces.util.AugmentationsImpl weblogic.apache.xerces.util.AugmentationsImpl$SmallContainer weblogic.apache.xerces.util.SymbolTable$Entry weblogic.apache.xerces.util.XMLAttributesImpl$Attribute weblogic.apache.xerces.xni.QName weblogic.apache.xerces.xni.QName[] weblogic.ejb.container.cache.CacheKey weblogic.ejb20.manager.SimpleKey weblogic.jdbc.common.internal.ConnectionEnv weblogic.jdbc.common.internal.StatementCacheKey weblogic.jms.common.Item weblogic.jms.common.JMSID weblogic.jms.frontend.FEConnection weblogic.logging.MessageLogger$1 weblogic.logging.WLLogRecord weblogic.rjvm.BubblingAbbrever$BubblingAbbreverEntry weblogic.rjvm.ClassTableEntry weblogic.rjvm.JVMID weblogic.rmi.cluster.ClusterableRemoteRef weblogic.rmi.internal.CollocatedRemoteRef weblogic.rmi.internal.PhantomRef weblogic.rmi.spi.ServiceContext[] weblogic.security.acl.internal.AuthenticatedSubject weblogic.security.acl.internal.AuthenticatedSubject$SealableSet weblogic.servlet.internal.ServletRuntimeMBeanImpl weblogic.transaction.internal.XidImpl weblogic.utils.collections.ConcurrentHashMap$Entry Oracle XA Transaction oracle.jdbc.driver.Binder[] oracle.jdbc.driver.OracleDatabaseMetaData oracle.jdbc.driver.T4C7Ocommoncall oracle.jdbc.driver.T4C7Oversion oracle.jdbc.driver.T4C8Oall oracle.jdbc.driver.T4C8Oclose oracle.jdbc.driver.T4C8TTIBfile oracle.jdbc.driver.T4C8TTIBlob oracle.jdbc.driver.T4C8TTIClob oracle.jdbc.driver.T4C8TTIdty oracle.jdbc.driver.T4C8TTILobd oracle.jdbc.driver.T4C8TTIpro oracle.jdbc.driver.T4C8TTIrxh oracle.jdbc.driver.T4C8TTIuds oracle.jdbc.driver.T4CCallableStatement oracle.jdbc.driver.T4CClobAccessor oracle.jdbc.driver.T4CConnection oracle.jdbc.driver.T4CMAREngine oracle.jdbc.driver.T4CNumberAccessor oracle.jdbc.driver.T4CPreparedStatement oracle.jdbc.driver.T4CTTIdcb oracle.jdbc.driver.T4CTTIk2rpc oracle.jdbc.driver.T4CTTIoac oracle.jdbc.driver.T4CTTIoac[] oracle.jdbc.driver.T4CTTIoauthenticate oracle.jdbc.driver.T4CTTIokeyval oracle.jdbc.driver.T4CTTIoscid oracle.jdbc.driver.T4CTTIoses oracle.jdbc.driver.T4CTTIOtxen oracle.jdbc.driver.T4CTTIOtxse oracle.jdbc.driver.T4CTTIsto oracle.jdbc.driver.T4CXAConnection oracle.jdbc.driver.T4CXAResource oracle.jdbc.oracore.OracleTypeADT[] oracle.jdbc.xa.OracleXAResource$XidListEntry oracle.net.ano.Ano oracle.net.ns.ClientProfile oracle.net.ns.ClientProfile oracle.net.ns.NetInputStream oracle.net.ns.NetOutputStream oracle.net.ns.SessionAtts oracle.net.nt.ConnOption oracle.net.nt.ConnStrategy oracle.net.resolver.AddrResolution oracle.sql.CharacterSet1Byte we are using Oracle BEA Weblogic 9.2 MP3 JDK 1.5.12 Oracle versoin 10.2.0.4 (for oracle we found one path which is needed to applied to avoid XA transaction memory leaks). But we are stuck to resolve SUN, BEA Weblgogic and Apache leaks. please suggest... regards, Amit J.

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  • WHich Implemtation of JSF 1.1 to USe MyFaces or Sun RI

    - by Macvin
    Hi, We want make a choice between SUN RI 1.1 JSF implementaiton and MyFaces . Appserver we will be using is Weblogic 8.1. Could you please rpovide main points for Comparison between the two Which one is better. Can we USe Facelets in SUN RI 1.1_02 . Which is the better choice if want to move the Application to JSF 1.2 and JDK 1.5 in Future. Thanks Mac

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  • Sun Access Manager

    - by bmw0128
    i'm looking to learn about SSO, and heard about Sun Access Manager and openSSO(?) I want to build a small system that does SSO, like have Apache as a front end working with an SSO server. Should I investigate Sun AM and is openSSO a product? Do they offer these free for developers? Thanks

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  • Sun App Server Deployment Error

    - by Nick Long
    Sun App Server Deployment : When choose to precompile JSP : Throw this error com.sun.enterprise.admin.common.exception.MBeanConfigException: Component not registered then have to do asadmin undeploy Anyone know what is the reason for this error?

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  • java applet won't work

    - by scoobi_doobi
    hey guys, this is homework stuff, but the question is not much about coding. the task is to write a java applet to work on an m-grid server. i have the server running on apache. it has a few sample applets in .jar and .class form. the .class versions work; the .jar versions work on appletviewer, but they break if I submit them as a job to the server with this: load: class examples/pixelcount/PixelCount.class not found. java.lang.ClassNotFoundException: examples.pixelcount.PixelCount.class at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Unknown Source) at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source) at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: java.net.ConnectException: Connection refused: connect at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(Unknown Source) at java.net.PlainSocketImpl.connectToAddress(Unknown Source) at java.net.PlainSocketImpl.connect(Unknown Source) at java.net.SocksSocketImpl.connect(Unknown Source) at java.net.Socket.connect(Unknown Source) at sun.net.NetworkClient.doConnect(Unknown Source) at sun.net.www.http.HttpClient.openServer(Unknown Source) at sun.net.www.http.HttpClient.openServer(Unknown Source) at sun.net.www.http.HttpClient.<init>(Unknown Source) at sun.net.www.http.HttpClient.New(Unknown Source) at sun.net.www.http.HttpClient.New(Unknown Source) at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown Source) at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source) at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source) at java.net.HttpURLConnection.getResponseCode(Unknown Source) at sun.plugin2.applet.Applet2ClassLoader.getBytes(Unknown Source) at sun.plugin2.applet.Applet2ClassLoader.access$000(Unknown Source) at sun.plugin2.applet.Applet2ClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) ... 7 more Exception: java.lang.ClassNotFoundException: examples.pixelcount.PixelCount.class I'm not really sure where exactly is the problem in here, given that they work on appletviewer. any help would be appreciated.. EDIT: don't know if I wrote it clearly. by ".class version" i refer to html file with this content: <applet height="300" width="450" code="examples/pixelcount/PixelCount.class"></applet> and ".jar" with this content: <applet height="300" width="450" archive="PixelCount.jar" code="examples.pixelcount.PixelCount.class"></applet>

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  • Don’t miss rare Venus transit across Sun on June 5th. Once in a life time event.

    - by Gopinath
    Space lovers here is a rare event you don’t want to miss. On June 5th or 6th of 2012,depending on which part of the globe you live, the planet Venus will pass across Sun and it will not happen again until 2117. During the six hour long spectacular transit you can see the shadow of Venus cross Sun. The transit of Venus occurs in pairs eight years apart, with the previous one taking place in 2004. The next pair of transits occurs after 105.5 & 121.5 years later. The best place to watch the event would be a planetarium nearby with telescope facility. If not you watch it directly but must protect your eyes at all times with proper solar filters. Where can we see the transit? The transit of Venus is going to be clearly visible in Europe, Asia, United States and some part of Australia. Americans will be able to see transit in the evening of Tuesday, June 5, 2012. Eurasians and Africans can see the transit in the morning of June 6, 2012. At what time the event occurs? The principal events occurring during a transit are conveniently characterized by contacts, analogous to the contacts of an annular solar eclipse. The transit begins with contact I, the instant the planet’s disk is externally tangent to the Sun. Shortly after contact I, the planet can be seen as a small notch along the solar limb. The entire disk of the planet is first seen at contact II when the planet is internally tangent to the Sun. Over the course of several hours, the silhouetted planet slowly traverses the solar disk. At contact III, the planet reaches the opposite limb and once again is internally tangent to the Sun. Finally, the transit ends at contact IV when the planet’s limb is externally tangent to the Sun. Event Universal Time Contact I 22:09:38 Contact II 22:27:34 Greatest 01:29:36 Contact III 04:31:39 Contact IV 04:49:35   Transit of Venus animation Here is a nice video animation on the transit of Venus Map courtesy of Steven van Roode, source NASA

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  • Parallel Classloading Revisited: Fully Concurrent Loading

    - by davidholmes
    Java 7 introduced support for parallel classloading. A description of that project and its goals can be found here: http://openjdk.java.net/groups/core-libs/ClassLoaderProposal.html The solution for parallel classloading was to add to each class loader a ConcurrentHashMap, referenced through a new field, parallelLockMap. This contains a mapping from class names to Objects to use as a classloading lock for that class name. This was then used in the following way: protected Class loadClass(String name, boolean resolve) throws ClassNotFoundException { synchronized (getClassLoadingLock(name)) { // First, check if the class has already been loaded Class c = findLoadedClass(name); if (c == null) { long t0 = System.nanoTime(); try { if (parent != null) { c = parent.loadClass(name, false); } else { c = findBootstrapClassOrNull(name); } } catch (ClassNotFoundException e) { // ClassNotFoundException thrown if class not found // from the non-null parent class loader } if (c == null) { // If still not found, then invoke findClass in order // to find the class. long t1 = System.nanoTime(); c = findClass(name); // this is the defining class loader; record the stats sun.misc.PerfCounter.getParentDelegationTime().addTime(t1 - t0); sun.misc.PerfCounter.getFindClassTime().addElapsedTimeFrom(t1); sun.misc.PerfCounter.getFindClasses().increment(); } } if (resolve) { resolveClass(c); } return c; } } Where getClassLoadingLock simply does: protected Object getClassLoadingLock(String className) { Object lock = this; if (parallelLockMap != null) { Object newLock = new Object(); lock = parallelLockMap.putIfAbsent(className, newLock); if (lock == null) { lock = newLock; } } return lock; } This approach is very inefficient in terms of the space used per map and the number of maps. First, there is a map per-classloader. As per the code above under normal delegation the current classloader creates and acquires a lock for the given class, checks if it is already loaded, then asks its parent to load it; the parent in turn creates another lock in its own map, checks if the class is already loaded and then delegates to its parent and so on till the boot loader is invoked for which there is no map and no lock. So even in the simplest of applications, you will have two maps (in the system and extensions loaders) for every class that has to be loaded transitively from the application's main class. If you knew before hand which loader would actually load the class the locking would only need to be performed in that loader. As it stands the locking is completely unnecessary for all classes loaded by the boot loader. Secondly, once loading has completed and findClass will return the class, the lock and the map entry is completely unnecessary. But as it stands, the lock objects and their associated entries are never removed from the map. It is worth understanding exactly what the locking is intended to achieve, as this will help us understand potential remedies to the above inefficiencies. Given this is the support for parallel classloading, the class loader itself is unlikely to need to guard against concurrent load attempts - and if that were not the case it is likely that the classloader would need a different means to protect itself rather than a lock per class. Ultimately when a class file is located and the class has to be loaded, defineClass is called which calls into the VM - the VM does not require any locking at the Java level and uses its own mutexes for guarding its internal data structures (such as the system dictionary). The classloader locking is primarily needed to address the following situation: if two threads attempt to load the same class, one will initiate the request through the appropriate loader and eventually cause defineClass to be invoked. Meanwhile the second attempt will block trying to acquire the lock. Once the class is loaded the first thread will release the lock, allowing the second to acquire it. The second thread then sees that the class has now been loaded and will return that class. Neither thread can tell which did the loading and they both continue successfully. Consider if no lock was acquired in the classloader. Both threads will eventually locate the file for the class, read in the bytecodes and call defineClass to actually load the class. In this case the first to call defineClass will succeed, while the second will encounter an exception due to an attempted redefinition of an existing class. It is solely for this error condition that the lock has to be used. (Note that parallel capable classloaders should not need to be doing old deadlock-avoidance tricks like doing a wait() on the lock object\!). There are a number of obvious things we can try to solve this problem and they basically take three forms: Remove the need for locking. This might be achieved by having a new version of defineClass which acts like defineClassIfNotPresent - simply returning an existing Class rather than triggering an exception. Increase the coarseness of locking to reduce the number of lock objects and/or maps. For example, using a single shared lockMap instead of a per-loader lockMap. Reduce the lifetime of lock objects so that entries are removed from the map when no longer needed (eg remove after loading, use weak references to the lock objects and cleanup the map periodically). There are pros and cons to each of these approaches. Unfortunately a significant "con" is that the API introduced in Java 7 to support parallel classloading has essentially mandated that these locks do in fact exist, and they are accessible to the application code (indirectly through the classloader if it exposes them - which a custom loader might do - and regardless they are accessible to custom classloaders). So while we can reason that we could do parallel classloading with no locking, we can not implement this without breaking the specification for parallel classloading that was put in place for Java 7. Similarly we might reason that we can remove a mapping (and the lock object) because the class is already loaded, but this would again violate the specification because it can be reasoned that the following assertion should hold true: Object lock1 = loader.getClassLoadingLock(name); loader.loadClass(name); Object lock2 = loader.getClassLoadingLock(name); assert lock1 == lock2; Without modifying the specification, or at least doing some creative wordsmithing on it, options 1 and 3 are precluded. Even then there are caveats, for example if findLoadedClass is not atomic with respect to defineClass, then you can have concurrent calls to findLoadedClass from different threads and that could be expensive (this is also an argument against moving findLoadedClass outside the locked region - it may speed up the common case where the class is already loaded, but the cost of re-executing after acquiring the lock could be prohibitive. Even option 2 might need some wordsmithing on the specification because the specification for getClassLoadingLock states "returns a dedicated object associated with the specified class name". The question is, what does "dedicated" mean here? Does it mean unique in the sense that the returned object is only associated with the given class in the current loader? Or can the object actually guard loading of multiple classes, possibly across different class loaders? So it seems that changing the specification will be inevitable if we wish to do something here. In which case lets go for something that more cleanly defines what we want to be doing: fully concurrent class-loading. Note: defineClassIfNotPresent is already implemented in the VM as find_or_define_class. It is only used if the AllowParallelDefineClass flag is set. This gives us an easy hook into existing VM mechanics. Proposal: Fully Concurrent ClassLoaders The proposal is that we expand on the notion of a parallel capable class loader and define a "fully concurrent parallel capable class loader" or fully concurrent loader, for short. A fully concurrent loader uses no synchronization in loadClass and the VM uses the "parallel define class" mechanism. For a fully concurrent loader getClassLoadingLock() can return null (or perhaps not - it doesn't matter as we won't use the result anyway). At present we have not made any changes to this method. All the parallel capable JDK classloaders become fully concurrent loaders. This doesn't require any code re-design as none of the mechanisms implemented rely on the per-name locking provided by the parallelLockMap. This seems to give us a path to remove all locking at the Java level during classloading, while retaining full compatibility with Java 7 parallel capable loaders. Fully concurrent loaders will still encounter the performance penalty associated with concurrent attempts to find and prepare a class's bytecode for definition by the VM. What this penalty is depends on the number of concurrent load attempts possible (a function of the number of threads and the application logic, and dependent on the number of processors), and the costs associated with finding and preparing the bytecodes. This obviously has to be measured across a range of applications. Preliminary webrevs: http://cr.openjdk.java.net/~dholmes/concurrent-loaders/webrev.hotspot/ http://cr.openjdk.java.net/~dholmes/concurrent-loaders/webrev.jdk/ Please direct all comments to the mailing list [email protected].

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  • What is bondib1 used for on SPARC SuperCluster with InfiniBand, Solaris 11 networking & Oracle RAC?

    - by user12620111
    A co-worker asked the following question about a SPARC SuperCluster InfiniBand network: > on the database nodes the RAC nodes communicate over the cluster_interconnect. This is the > 192.168.10.0 network on bondib0. (according to ./crs/install/crsconfig_params NETWORKS> setting) > What is bondib1 used for? Is it a HA counterpart in case bondib0 dies? This is my response: Summary: bondib1 is currently only being used for outbound cluster interconnect interconnect traffic. Details: bondib0 is the cluster_interconnect $ oifcfg getif            bondeth0  10.129.184.0  global  public bondib0  192.168.10.0  global  cluster_interconnect ipmpapp0  192.168.30.0  global  public bondib0 and bondib1 are on 192.168.10.1 and 192.168.10.2 respectively. # ipadm show-addr | grep bondi bondib0/v4static  static   ok           192.168.10.1/24 bondib1/v4static  static   ok           192.168.10.2/24 Hostnames tied to the IPs are node1-priv1 and node1-priv2  # grep 192.168.10 /etc/hosts 192.168.10.1    node1-priv1.us.oracle.com   node1-priv1 192.168.10.2    node1-priv2.us.oracle.com   node1-priv2 For the 4 node RAC interconnect: Each node has 2 private IP address on the 192.168.10.0 network. Each IP address has an active InfiniBand link and a failover InfiniBand link. Thus, the 4 node RAC interconnect is using a total of 8 IP addresses and 16 InfiniBand links. bondib1 isn't being used for the Virtual IP (VIP): $ srvctl config vip -n node1 VIP exists: /node1-ib-vip/192.168.30.25/192.168.30.0/255.255.255.0/ipmpapp0, hosting node node1 VIP exists: /node1-vip/10.55.184.15/10.55.184.0/255.255.255.0/bondeth0, hosting node node1 bondib1 is on bondib1_0 and fails over to bondib1_1: # ipmpstat -g GROUP       GROUPNAME   STATE     FDT       INTERFACES ipmpapp0    ipmpapp0    ok        --        ipmpapp_0 (ipmpapp_1) bondeth0    bondeth0    degraded  --        net2 [net5] bondib1     bondib1     ok        --        bondib1_0 (bondib1_1) bondib0     bondib0     ok        --        bondib0_0 (bondib0_1) bondib1_0 goes over net24 # dladm show-link | grep bond LINK                CLASS     MTU    STATE    OVER bondib0_0           part      65520  up       net21 bondib0_1           part      65520  up       net22 bondib1_0           part      65520  up       net24 bondib1_1           part      65520  up       net23 net24 is IB Partition FFFF # dladm show-ib LINK         HCAGUID         PORTGUID        PORT STATE  PKEYS net24        21280001A1868A  21280001A1868C  2    up     FFFF net22        21280001CEBBDE  21280001CEBBE0  2    up     FFFF,8503 net23        21280001A1868A  21280001A1868B  1    up     FFFF,8503 net21        21280001CEBBDE  21280001CEBBDF  1    up     FFFF On Express Module 9 port 2: # dladm show-phys -L LINK              DEVICE       LOC net21             ibp4         PCI-EM1/PORT1 net22             ibp5         PCI-EM1/PORT2 net23             ibp6         PCI-EM9/PORT1 net24             ibp7         PCI-EM9/PORT2 Outbound traffic on the 192.168.10.0 network will be multiplexed between bondib0 & bondib1 # netstat -rn Routing Table: IPv4   Destination           Gateway           Flags  Ref     Use     Interface -------------------- -------------------- ----- ----- ---------- --------- 192.168.10.0         192.168.10.2         U        16    6551834 bondib1   192.168.10.0         192.168.10.1         U         9    5708924 bondib0   There is a lot more traffic on bondib0 than bondib1 # /bin/time snoop -I bondib0 -c 100 > /dev/null Using device ipnet/bondib0 (promiscuous mode) 100 packets captured real        4.3 user        0.0 sys         0.0 (100 packets in 4.3 seconds = 23.3 pkts/sec) # /bin/time snoop -I bondib1 -c 100 > /dev/null Using device ipnet/bondib1 (promiscuous mode) 100 packets captured real       13.3 user        0.0 sys         0.0 (100 packets in 13.3 seconds = 7.5 pkts/sec) Half of the packets on bondib0 are outbound (from self). The remaining packet are split evenly, from the other nodes in the cluster. # snoop -I bondib0 -c 100 | awk '{print $1}' | sort | uniq -c Using device ipnet/bondib0 (promiscuous mode) 100 packets captured   49 node1-priv1.us.oracle.com   24 node2-priv1.us.oracle.com   14 node3-priv1.us.oracle.com   13 node4-priv1.us.oracle.com 100% of the packets on bondib1 are outbound (from self), but the headers in the packets indicate that they are from the IP address associated with bondib0: # snoop -I bondib1 -c 100 | awk '{print $1}' | sort | uniq -c Using device ipnet/bondib1 (promiscuous mode) 100 packets captured  100 node1-priv1.us.oracle.com The destination of the bondib1 outbound packets are split evenly, to node3 and node 4. # snoop -I bondib1 -c 100 | awk '{print $3}' | sort | uniq -c Using device ipnet/bondib1 (promiscuous mode) 100 packets captured   51 node3-priv1.us.oracle.com   49 node4-priv1.us.oracle.com Conclusion: bondib1 is currently only being used for outbound cluster interconnect interconnect traffic.

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  • Parallel Environment (PE) on Sun Grid Engine (6.2u5) won't run jobs: "only offers 0 slots"

    - by Peter Van Heusden
    I have Sun Grid Engine set up (version 6.2u5) on a Ubuntu 10.10 server with 8 cores. In order to be able to reserve multiple slots, I have a parallel environment (PE) set up like this: pe_name serial slots 999 user_lists NONE xuser_lists NONE start_proc_args /bin/true stop_proc_args /bin/true allocation_rule $pe_slots control_slaves FALSE job_is_first_task TRUE urgency_slots min accounting_summary FALSE This is associated with the all.q on the server in question (let's call the server A). However, when I submit a job that uses 4 threads with e.g. qsub -q all.q@A -pe serial 4 mycmd.sh, it never gets scheduled, and I get the following reasoning from qstat: cannot run in PE "serial" because it only offers 0 slots Why is SGE saying "serial" only offers 0 slots, since there are 8 slots available on the server I specified (server A)? The queue in question is configured thus (server names changed): qname all.q hostlist @allhosts seq_no 0 load_thresholds np_load_avg=1.75 suspend_thresholds NONE nsuspend 1 suspend_interval 00:05:00 priority 0 min_cpu_interval 00:05:00 processors UNDEFINED qtype BATCH INTERACTIVE ckpt_list NONE pe_list make orte serial rerun FALSE slots 1,[D=32],[C=8], \ [B=30],[A=8] tmpdir /tmp shell /bin/sh prolog NONE epilog NONE shell_start_mode posix_compliant starter_method NONE suspend_method NONE resume_method NONE terminate_method NONE notify 00:00:60 owner_list NONE user_lists NONE xuser_lists NONE subordinate_list NONE complex_values NONE projects NONE xprojects NONE calendar NONE initial_state default s_rt INFINITY h_rt 08:00:00 s_cpu INFINITY h_cpu INFINITY s_fsize INFINITY h_fsize INFINITY s_data INFINITY h_data INFINITY s_stack INFINITY h_stack INFINITY s_core INFINITY h_core INFINITY s_rss INFINITY h_rss INFINITY s_vmem INFINITY h_vmem INFINITY,[A=30g], \ [B=5g]

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  • Sun Grid Engine (SGE) / limiting simultaneous array job sub-tasks

    - by wfaulk
    I am installing a Sun Grid Engine environment and I have a scheduler limit that I can't quite figure out how to implement. My users will create array jobs that have hundreds of sub-tasks. I would like to be able to limit those jobs to only running a set number of tasks at the same time, independent of other jobs. Like I might have one array job that I want to run 20 tasks at a time, and another I want to run 50 tasks at a time, and yet another that I'm fine running without limit. It seems like this ought to be doable, but I can't figure it out. There's a max_aj_instances configuration option, but that appears to apply globally to all array jobs. I can't see any way to use consumable resources, as I'd need a "complex attribute" that is per-job, and that feature doesn't seem to exist. It didn't look like resource quotas would work, but now I'm not so sure of that. It says "A resource quota set defines a maximum resource quota for a particular job request", but it's unclear if an array job's sub-tasks' resource requests will be aggregated for the purposes of the resource quota. I'm going to play with this, but hopefully someone already knows outright.

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  • Healthcare and Distributed Data Don't Mix

    - by [email protected]
    How many times have you heard the story?  Hard disk goes missing, USB thumb drive goes missing, laptop goes missing...Not a week goes by that we don't hear about our data going missing...  Healthcare data is a big one, but we hear about credit card data, pricing info, corporate intellectual property...  When I have spoken at Security and IT conferences part of my message is "Why do you give your users data to lose in the first place?"  I don't suggest they can't have access to it...in fact I work for the company that provides the premiere data security and desktop solutions that DO provide access.  Access isn't the issue.  'Keeping the data' is the issue.We are all human - we all make mistakes... I fault no one for having their car stolen or that they dropped a USB thumb drive. (well, except the thieves - I can certainly find some fault there)  Where I find fault is in policy (or lack thereof sometimes) that allows users to carry around private, and important, data with them.  Mr. Director of IT - It is your fault, not theirs.  Ms. CSO - Look in the mirror.It isn't like one can't find a network to access the data from.  You are on a network right now.  How many Wireless ones (wifi, mifi, cellular...) are there around you, right now?  Allowing employees to remove data from the confines of (wait for it... ) THE DATA CENTER is just plain indefensible when it isn't required.  The argument that the laptop had a password and the hard disk was encrypted is ridiculous.  An encrypted drive tells thieves that before they sell the stolen unit for $75, they should crack the encryption and ascertain what the REAL value of the laptop is... credit card info, Identity info, pricing lists, banking transactions... a veritable treasure trove of info people give away on an 'encrypted disk'.What started this latest rant on lack of data control was an article in Government Health IT that was forwarded to me by Denny Olson, an Oracle Principal Sales Consultant in Minnesota.  The full article is here, but the point was that a couple laptops went missing in a couple different cases, and.. well... no one knows where the data is, and yes - they were loaded with patient info.  What were you thinking?Obviously you can't steal data form a Sun Ray appliance... since it has no data, nor any storage to keep the data on, and Secure Global Desktop allows access from Macs, Linux and Windows client devices...  but in all cases, there is no keeping the data unless you explicitly allow for it in your policy.   Since you can get at the data securely from any network, why would you want to take personal responsibility for it?  Both Sun Rays and Secure Global Desktop are widely used in Healthcare... but clearly not widely enough.We need to do a better job of getting the message out -  Healthcare (or insert your business type here) and distributed data don't mix. Then add Hot Desking and 'follow me printing' and you have something that Clinicians (and CSOs) love.Thanks for putting up my blood pressure, Denny.

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  • Getting no class def found error. Log4J -> Java

    - by Nitesh Panchal
    Hello, I created a simple web application and added log4J's jar in my lib folder and it seems to work fine. Then i created a Ejb module and did the same thing of adding jar file in my classpath, but i am getting this error :- Caused by: javax.ejb.TransactionRolledbackLocalException: Exception thrown from bean: java.lang.NoClassDefFoundError: org/apache/log4j/Logger at com.sun.ejb.containers.BaseContainer.checkExceptionClientTx(BaseContainer.java:4929) at com.sun.ejb.containers.BaseContainer.postInvokeTx(BaseContainer.java:4761) at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:1955) ... 94 more Caused by: java.lang.NoClassDefFoundError: org/apache/log4j/Logger at common.Utils.getRssFeed(Utils.java:128) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1052) at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1124) at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:5243) at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:615) at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:797) at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:567) at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doAround(SystemInterceptorProxy.java:157) at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:139) at sun.reflect.GeneratedMethodAccessor102.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:858) at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:797) at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:367) at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:5215) at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:5203) at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:190) ... 92 more I don't even have any other version of log4j in classpath. Any idea why is this error coming? Actually first i created a Enterprise application and everything seemed to work fine. But then, i copied files from my enterprise application's ejb module to a separate module and since then these errors are coming. This is in my build-impl.xml :- <target depends="compile" name="library-inclusion-in-archive"> <copyfiles files="${libs.Log4J.classpath}" todir="${build.classes.dir}"/> </target> <target depends="compile" name="library-inclusion-in-manifest"> <copyfiles files="${libs.Log4J.classpath}" todir="${dist.ear.dir}/lib"/> <manifest file="${build.ear.classes.dir}/META-INF/MANIFEST.MF" mode="update"/> </target> Don't know why is this pointing to ear instead of jar. Is there any problem with the above statement? How do i resolve this? I am using Netbeans 6.8 Thanks in advance :)

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  • Bridging Virtual Networking into Real LAN on a OpenNebula Cluster

    - by user101012
    I'm running Open Nebula with 1 Cluster Controller and 3 Nodes. I registered the nodes at the front-end controller and I can start an Ubuntu virtual machine on one of the nodes. However from my network I cannot ping the virtual machine. I am not quite sure if I have set up the virtual machine correctly. The Nodes all have a br0 interfaces which is bridged with eth0. The IP Address is in the 192.168.1.x range. The Template file I used for the vmnet is: NAME = "VM LAN" TYPE = RANGED BRIDGE = br0 # Replace br0 with the bridge interface from the cluster nodes NETWORK_ADDRESS = 192.168.1.128 # Replace with corresponding IP address NETWORK_SIZE = 126 NETMASK = 255.255.255.0 GATEWAY = 192.168.1.1 NS = 192.168.1.1 However, I cannot reach any of the virtual machines even though sunstone says that the virtual machine is running and onevm list also states that the vm is running. It might be helpful to know that we are using KVM as a hypervisor and I am not quite sure if the virbr0 interface which was automatically created when installing KVM might be a problem.

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  • How To Set Up A Loadbalanced High-Availability Apache Cluster On Windows

    - by bReAd
    Setting up a two-node Apache web server cluster that provides high-availability. In front of the Apache cluster we create a load balancer that splits up incoming requests between the two Apache nodes. Because we do not want the load balancer to become another “Single Point Of Failure”, we must provide high-availability for the load balancer, too. Therefore our load balancer will in fact consist out of two load balancer nodes that monitor each other using heartbeat, and if one load balancer fails, the other takes over silently. The following setup is proposed: Apache node 1: webserver1.example.com (webserver1) – IP address: 192.168.0.101; Apache document root: /var/www Apache node 2: webserver2.example.com (webserver2) – IP address: 192.168.0.102; Apache document root: /var/www Load Balancer node 1: loadb1.example.com (loadb1) – IP address: 192.168.0.103 Load Balancer node 2: loadb2.example.com (loadb2) – IP address: 192.168.0.104 Virtual IP Address: 192.168.0.105 (used for incoming requests) Currently, there are many solutions for Linux machines and there aren't any on windows. I've tried searching a long time for solutions on Windows platform How do I create the virtual IP in windows and perform monitoring and make the load balancer listen to the virtual IP Address?

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  • Clustering/load balancing for cluster unaware applications

    - by AaronLS
    Forgive me if I use any of these terms incorrectly. I am wondering if there is any kind of software that would allow my two "join" two computers together such that a cluster unaware application could utilize their combined computing resources? By "cluster unaware" I mean an application that isn't designed to share work across multiple services. My understanding is that clustering is enabled by the specific application by it's architecture, such that messaging with multiple instances of the application coordinate the sharing of work. Instead I am looking for something that enables clustering at the OS or virtualization level, so that any application could essentially be clustered. Failing that, I am also wondering about the following scenario: We have 3 different applications we will call A, B, and C. We have 2 single core computers. At any given time lets say that any combination of those applications will be CPU intensive. In cases where only 2 of those apps are very active, have one of them moved over to a different server. In a nutshell, some sort of dynamic automatic shuffling of the application's load. I have heard of virtual machines that can be migrated across physical machines while live, but I am wondering if this can be done automatically in response to an application's or VM's CPU activity?

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  • Linux HA / cluster: what are the differences between Pacemaker, Heartbeat, Corosync, wackamole?

    - by Continuation
    Can you help me understand Linux HA? Pacemaker, Heartbeat, Corosync seem to be part of a whole HA stack, but how do they fit together? How does wackamole differ from Pacemaker/Heartbeat/Corosync? I've seen opinions that wackamole is better than Heartbeat because it's peer-based. Is that valid? The last release of wackamole was 2.5 years ago. Is it still being maintained or active? What would you recommend for HA setup for web/application/database servers?

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  • PostgreSQL failover cluster on Windows Server

    - by user36997
    We are looking for advice on how to setup a basic failover cluster for our application: We will be using 4 machines running Microsoft Windows Server (most probably 2003). All four will always run our application, which is essentially a web service. Load balancing is "outsourced" - somebody else handles the distribution of the web requests among the servers. Only one of the servers will be running the PostgreSQL server actively at any given time. Another server (of the four) also has the DB installed, but is on standby/passive. The DB data is stored on shared storage. No copying data between servers. Reads are done very frequently by many end-users, and in rather small chunks of data. Writes are done much less frequently, by less users, and in very large bulks of data. Now, how can one configure Microsoft Cluster Service to keep only one instance of the DB server and 4 instances (1 per server) of our application at all times? And does PostgreSQL integrate neatly with MSCS at all? Update: Instead of keeping the data on shared storage, I also consider using log shipping to replicate data on a couple of DB servers. There are two issues with this option: Log shipping only makes sure that I have a second server that gets all of the data and is ready to take over. How do I implement the actual failure detection and failover switch? Switching back: Suppose the master fails and the system automatically fails over to the slave, and later the master comes back online. I understand that with WAL shipping this will require to reconfigure the log shipping once again, and that switching back is far from seamless. Is that so?

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