A computer cluster consists of a set of loosely connected computers that work together so that in many respects they can be viewed as a single system.

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What is a reasonable latency time for mpdringtest with gigabit ethernet?

Hi I have a small test network that I'm using to do some number crunching for my dissertation. My network consists of three machines with intel gigabit network cards (all em drivers with two hosts ...
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2answers
660 views

Heavy write to Galera cluster - table locked, cluster practically unusable

I set up Galera Cluster on 3 nodes. It works perfectly for reading data. I have done simple application to make some test on the cluster. Unfortunately I have to say that the Cluster fails totally ...
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22 views

How to correlate apache events among a web cluster?

We have a cluster of about 200 web servers. From time to time we'll have an event occur where a subset of those servers will trigger the monitoring software to restart the apache daemon. We can get ...
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2answers
1k views

How to set up Zabbix to monitor SQL Server Failover Active-Passive Cluster?

It should be simple, so it is just most likely my approach being totally off and someone will hopefully prod me into the right direction. We have a Zabbix 2.0.3 server instance set up monitoring a ...
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1answer
904 views

SQL Server 2008 R2 cluster, “available storage” shows “offline”

I've installed a SQL Server 2008 R2 cluster and I found the resource group "available storage" shows "offline" status. What does it mean? It seems I can't take it online. I tried to use the cluster ...
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9 views

Weblogic Cluster returns URL of dead instance in WSDL

We have a clustered Oracle 11g (in fact an OSB) that exposes a JAX-RPC service. When we call http://host2:7102/Foo/FooSvc?WSDL (host2), we get back: <L5G3N2:service name="FooService"> ...
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4answers
80 views

How do I change multiple linux servers' /etc/fstab simultaneously

We have plenty of linux server that will mount a few linux file server by NFS or SMB using /etc/fstab But manually changing each server's /etc/fstab is very tedious. Is there any way to edit ...
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1answer
25 views

How remote instances work on Coldfusion Clustering?

I have just decided to set up my site using ColdFusion clustering in the staging environment. I need to find out what code adjustments are required when we move to a cluster environment. I have two ...
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1answer
643 views

sql server 2008 cluster hang when a heavy load is run

we have a sql server 2008 active/active cluster running on wondows 2008R2 O/S. 14GB RAM, 4xCPU. we have set a ceiling of 12GB for sql server. We're running an agent job which loads 3 million records ...
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7 views

how do you manage all the nodes in pbs batch servers? [closed]

In a cluster with pbs batch system installed for scientific computing, all the nodes are configured for conducting computational work and storing files. as a manager, It is necessary to know the cpu ...
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1answer
30 views

IBM V7000 firmware upgrade effect on mounted LUN

We've IBM storwize V7000 Storage where the firmware is going to be upgraded to latest version.. This will require a reboot to the storage. I've got arround 10 LUN's (almost 10TB) coming from this ...
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1answer
942 views

Tomcat mod_jk cluster skip 404 http status

I am trying Tomcat Clustering with mod_jk for months and so far not so bad but facing a problem during deployment. I am using FarmDeployer to copy and deploy the WAR to other nodes in the cluster but ...
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1answer
28 views

Riak all_nodes_down error but they are up

I built a Riak cluster on three Raspberry Pi computers. vm.args and app.config files are double checked on each node (static IP addresss are correct). All nodes are valid: # ./riak-admin ...
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2answers
22 views

Adding a 3rd node to an existing DRBD cluster

We currently have a 2 node DRBD cluster running which we would like to add a third node to. I have so far been unable to find any resources on whether it is possible to add a third node to an existing ...
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1answer
35 views

Monitoring heartbeat centos

I am using HAproxy on two servers and for high availability using heartbeat and everything is okay, but I want to monitoring heartbeat I have a long search and get clustat command but can't find it on ...
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1answer
20 views

Riak does not allow to add a node because it is in its own cluster

(this is a repost of my question from stack overflow, it was offtopic there, here is right place to ask it) I was trying to build a Riak cluster on Raspberry Pi. Created an image with Erland and ...
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1answer
594 views

Why do Layer 7 load balancers configuration not require any client configuration changes?

For example, for haproxy (layer 7) load balancing, you only need to configure the "real servers" or "backends" behind the VIP (i.e., cluster IP). E.g.: listen smtp 192.168.3.10:25 mode tcp ...
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1answer
18 views

PostgreSQL asynchronous cluster with partial synchronous commits

We`re planning a complete synchronous PG Cluster with 3 nodes but we asked ourselves if its possible to have an asynchronous cluster with partial synchronous commits. Normally you make your cluster ...
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1answer
93 views

Load balancing glassfish v4.0 CLUSTER with apache HTTP server: Location of apache

I am teaching myself to build clustered Java EE 7 applications. I am focused on Glassfish Server v4.0. Based on the official documentation (Chapter 7 page 133) , Glassfish can be loadbalanced using ...
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3answers
46 views

Is it safe to have backup and production servers in the same cluster?

I have two virtual servers maintained by the same provider. I asked them to place them on different physical machines. They told me that they placed them in different nodes of one cluster. I do not ...
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1answer
61 views

Does ColdFusion single server clustering using multiple instances provides any performance enhancement?

I have few doubts regarding Coldfusion clustering. Is there any benefits of Creating multiple instances of a single ColdFusion server, Create a cluster by adding those instances and host the ...
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1answer
35 views

Tomcat cluster - how to verify node starvation?

We have a tomcat cluster with a load balancer (haproxy). As part of our upgrade script we would like to starve a single tomcat in the cluster of 3, wait until all the requests are handled for that ...
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1answer
655 views

What's the best way to manage product images in a Magento Cluster?

I'm running Magento CE on multiple web node. The Admin Backend is always running on the same server, so all the images are uploaded on this server. On my
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1answer
863 views

SQL Cluster P2V Physical to Virtual Migration tips?

Need tips for those migrating a MSSQL cluster to a single Hyper-V guest VM. Context: these are P2V (Physical to Virtual) of only one node, taking a snapshot of all drives and dismantling/destroying ...
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2answers
65 views

Can I format a Veritas cluster shared volume from windows?

We have a Microsoft Failover Cluster with dynamic disks managed by Veritas Storage Foundation. Today the sysadmins added a new disk for SQL Server but the cluster size on the volume was wrong, so I ...
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54 views

Using Openfire for distributed XMPP-based video-chat

I have been tasked with setting up a distributed video-chat system built on XMPP. Currently my setup looks like this: Openfire (XMPP server) + JingleNodes plugin for video chat OpenLDAP (LDAP ...
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1answer
321 views

Failover Cluster Client Access Point Only Responds to Pings on the Owner Node

Background We're running two VMs (Windows Server 2012 R2) on Azure with SQL Server installed, set up as an availability group. We also, of course, have another VM as a dedicated DC. These are all ...
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1answer
121 views

Make a Docker application write to stdout

I'm deploying a 3rd-party application in compliance with the 12 factor advisory, and one of the points tell that application logs should be printed to stdout/stderr: then clustering software can ...
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1answer
5k views

Load Balancing and Clustering using mod_proxy_ajp on Apache HTTP Server 2.2.21 and Tomcat 7.0.23

I've been struggling to make load balancing and clustering working using these combination: Apache HTTP Server 2.2.21 (httpd-2.2.21-win32-x86-openssl-0.9.8r) using mod_proxy_ajp with sticky session ...
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1answer
63 views

IIS Shared Configuration Share for Cluster FTP Service on Server 2008 R2

Microsoft gives the following order for setting up the Clustered FTP (after installing IIS, FTP Service, and setting up your Cluster): Set up a file share that will be used for IIS Shared ...
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1answer
131 views

Best method to share ISCSI lun across cluster of app servers

I'm in the process of migrating our cluster to new hardware. We use bare metal servers, no virtualization. Currently, we have around 30 "application" servers. When we make an update, we push the ...
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40 views

What do I need to increase my processing power?

Ok so I have written this program in Python 2.7 that runs on a desktop machine running Arch Linux. Without getting into the big details, this program takes a data-point, performs a series of ...
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5answers
105 views

send files to dozens of servers quickly

We have a cluster of machines (around 50 and growing). Each machine has a search index that needs to be updated multiple times per day. We currently update the index on each machine individually, but ...
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23 views

Homogeneous cluster versus heterogeneous cluster

By homogeneous cluster I mean a cluster of nodes that all have the same services running. I am trying to set up a cluster of nodes that offer a set of services. The cluster can respond to HTTPS ...
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36 views

DFS Replication Manager on Failover Cluster Nodes

I currently have a VM architecture setup for high availability / manageability. The one point of failure is that I have a single windows 2008 machine that runs DFS replication across the servers in my ...
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2answers
65 views

High Low priority queues SGE

I would like to have two queues in a CPU/GPU cluster, one with high priority and one with low priority. Thus, jobs that are submitted in the high priority queue will be bumped to the top of the list ...
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263 views

Apache Kafka consumer client connecting to Apache Zookeeper: EndOfStreamException

I get an error when trying to 'consume' messages from Kafka (2.9.2-0.8.1) with a Zookeer stand-alone (3.4.5). You can see the source code below as well as the error message and logfile from Zookeeper. ...
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27 views

MSTDC in SQL Server 2012 - Windows Server 2012 R2 with high availability

We had implemented SQL Server High Availability on two physical servers over the VPN network. SQL Server 2012, Windows Server 2012 R2. It was noted that, Distributed Transaction was working perfectly ...
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1answer
181 views

Using DHCP, is it possible to obtain an IP address & MAC address for a cluster? [closed]

I know that DHCP assigns IP addresses, but does it also assign a MAC address? Is this a commonly used paradigm for cluster/cloud computing? Perhaps DHCP could be used to dynamically assign a new IP ...
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5answers
2k views

one fast VM on many slow hosts?

Is there any VM host software that supports a host-cluster, where it sums all (physical) RAMs to one big (virtual) RAM, and maps the many host-CPUs (in many PCs) to some (virtual) multi-core setup? ...
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42 views

How can I run a CentOS (Red Hat) cluster in degraded mode?

I've installed Red Hat's cluster software on an install of CentOS 6.5, and use it to provide redundant routing from one network to another. This works fine, and I have a pair of boxes providing the ...
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4answers
2k views

Are there any good guidelines for building a KVM Cluster on Red Hat

I am looking to understand how other people have built clusters of KVM host servers. I am especially interested in how people solved the problem of having them automatically failover if one node dies? ...
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49 views

How to configure a dovecot cluster with non-shared storage

Dovecot has a Proxy service which allows to perform load balancing between Dovecot Backend servers. And there is a Director service which makes it easy to have temporarily user -> server mapping. ...
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3answers
2k views

NLB Accessed Denied from second server

Have NLB set up and working. Just two servers, web1 and web2. I set up NLB on web1 and can view both machines as Converged. (I had to specify a login/pass to connect to web2). On web2, looking at the ...
2
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1answer
123 views

Beowulf cluster storage setup [closed]

I'm a Computer Engineering student working on a project with a Verari blade cluster, a bit outdated for today standards. I had acquired some Unix experience but I'm not an expert at all. This Verari ...
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23 views

How to Install CentOS on a Cluster

I want to install CentOS on a cluster with a main node and five identical slave nodes. I have installed CentOS 6.5 on my head node and I have ssh as root. I moved /dev/sda from the first slave to the ...
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19 views

What mysql configuration offers the highest write performance

Which multiple mysql server configuration offers the highest write performance? We are looking at changing a web application which is heavy write and want to know what configuration is going to give ...
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0answers
70 views

starcluster ec2 403 forbidden

I am trying to setup a Hadoop cluster using MIT's starcluster tool, I have modified the configuration file with my AWS information, but am getting the following error message: !!! ERROR - ...
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1answer
138 views

Pgpool configuration with Liferay cluster

I'm using a Liferay cluster connected to pgpool2 and when I run heavy user activity against the web servers I see a lot of exceptions regarding liferay unable to establish a connection to the DB. ...
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32 views

Redundant load balancing using Apache

I have a cluster of 5 application servers with a single Apache HTTP server sitting in front of them acting as a load balancer (using mod_proxy_ajp). This works well, but the problem is that the load ...