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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PostgreSQL replication lag Ubuntu 11.10/12.04

I've a PostgreSQL cluster running on Amazon AWS EC2 instances with streaming replication and "hot standby" option enabled. I'm now gradually upgrading it from Ubuntu 11.10 to Ubuntu 12.04 LTS and I've ...
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1answer
738 views

MariaDB Galera Clustering - Active Active - Operation not permitted error

I am having issues with MariaDB and Galera running on RHEL 6.4 & 6.2 64bit servers and getting them to cluster. I installed the required RPM's for Galera clustering: MariaDB-Galera-server ...
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60 views

Firewall rules between windows cluster

I have been given the task to define firewall rules between 2 Windows clusters. The first cluster hosts a clustered middleware application and the second cluster hosts SQL Server. The 2 clusters are ...
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1answer
167 views

HAProxy SSL connection error

Brand new to setting up SSL with HAProxy and Litespeed load balancer, just generated my certificate using the .csr and am trying to have HAProxy terminate SSL before sending it to the web worker ...
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1answer
34 views

Running jobs in a HPC cluster [closed]

I'm quite new to HPC environment. Is there any difference in running a job on a node utilizing 8 cores and running the same job on 8 nodes utilizing I core in terms of performance or walltime used. ...
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1answer
116 views

Liferay cluster with SAN storage with ext3 [duplicate]

I'm deploying an liferay portal in a cluster which has 2 node load balanced, and config both to access to the same data location in a SAN storage devide. The problem is each node can not see the other ...
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1answer
52 views

How to create a slurm queue for the headnode

Is there a way to create a SLURM queue that runs on the headnode? I'd like to be able to do this as a first level testing queue sort of, before trying to run on multiple nodes. I've tried stuff ...
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2answers
208 views

MySQL geographic replication cloud

I currently have a standard local LAMP setup, (2 web servers, master/slave MySQL, load balancer). This is severing me well locally, but my global users experience slowness. I want to setup some ...
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2answers
190 views

Oracle Weblogic 10.3.5 Cluster creation issues

I'm trying to create a two node cluster with Oracle Weblogic 10.3.5. During the "Fusion Middleware Configuration Wizard" setup process, I'm not sure what to put in for the "Cluster Address" if I ...
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2answers
774 views

Why has Red Hat Cluster Suite stopped working?

I've been testing the Cluster Suite on CentOS 6.4, and had it working fine, but I noticed today [8th August, when this question was originally asked] that it's not liking the config that was ...
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1answer
318 views

MariaDB Galera Cluster hang after issue cluster command

When trying to cluster two MariaDB Galera servers on RHEL 6 together using the command: mysqld -uroot --wsrep_cluster_address=gcomm:// and the screen then sits there, and looks at me with this ...
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1answer
328 views

When trying to delete a table from NDB Cluster, I get the error “4243: Index not found”

In a Linux-based NDB-cluster consisting of 7 API nodes, 1 Management node and 4 NDB nodes, I am trying to drop a table. When I try to drop the table using MySQL Client, I receive the following ...
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337 views

Is there a programmatic way to determine free disk space on a Linux server?

I have a collection of Linux servers, each of which has a local hard drive with a /tmp directory. Occasionally, the /tmp directory on a server will fill up and cause errors. I want to automate the ...
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1answer
155 views

Is it possible to speed up network filesystem by sth like unionfs, aufs?

I need to speed up slow, large storage with local SSD drive. I figured out I could do this with union filesystems. Here are results with nginx reading data from: local SSD alone: ~140 ...
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380 views

How to configure cluster.conf for failover routing two networks?

I'm routing between an "external" subnet with Internet connectivity and two "internal" subnets, using iptables forwarding on a Linux box running CentOS 6.4: I'd like to now duplicate this router ...
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2answers
6k views

2012 Cluster service name failing

I have successfully created a cluster, but any services I try to cluster fail with the same or similar symptoms (I have tried clustering DTC and installing a SQL cluster). Environment: 2 – nodes – ...
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1answer
691 views

When creating a Win2012 cluster “The network name is already used on the network” no matter what name is used

I have a test setup that has 2 Windows Server 2012 VMs on Hyper-V joined to a windows 2008 R2 domain - there is an internal network whose DNS server is on the domain controller and an external network ...
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1answer
272 views

Heartbeat meatware STONITH on kernel panic

I have a two node cluster with heartbeat and DRBD managing a mysql resource. The failover works great if I halt the primary, reboot it, or disconnect the network connection. However, if the primary ...
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1answer
339 views

RedHat 6 Cluster Failover

I'm testing the RedHat Cluster Administration tool documented here: https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Cluster_Administration/index.html I have two ...
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1answer
72 views

Detect if the original node failed in tomcat cluster

I have two nodes in a cluster. Node1 initially servers requests. Loadbalancer redirects the request to node 2 if the first node fails. I would like to know if there is a way for the Node 2 to detect ...
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1answer
75 views

Intelligent, Location Dependent DNS

I'm new to complex network infrastructure but I'm quickly realizing that we're outgrowing our centralized load balanced cluster. The way we have things setup right now means that in order to add a ...
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1answer
472 views

Session replication in Tomcat

I have setup my cluster with one loadbalancer and 2 nodes with sticky session. I am using mod_jk for loadbalancing. I am having problem with proper session replication. I am using Tomcat 6. When I ...
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1answer
58 views

Authenticate ftp users on mysql through secure channel

I've to face this problem regarding security: some sFTP servers (proftpd) in a dmz that need to authenticate users against a mysql (native cluster|percona cluster|MariaDB cluster) through a secure ...
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2answers
147 views

What “pieces” are needed in order to set up a cluster of physical servers?

Background: Currently, we use Rackspace cloud servers. We have no intention to stop using them, but would like to look into setting up a cluster of physical servers (probably desktop computers in the ...
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1answer
1k views

WARNING: Context manager doesn't exist

I have cluster setup with session replication. I have one load balancer with 2 tomcat instances as the worker nodes. In one of the node I am getting the WARNING. NOt sure what it really means. Session ...
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1answer
198 views

Hyper-V - USB Disk mapped to VM

If I have a VM on a Hyper-V host with an IP 192.168.50.25 (VM IP), where the Host has an IP of 192.168.40.25. (The host itself has a virtual switch whose NIC patches into a procurve onto the VLAN ...
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1answer
41 views

Coherent logs from multiple identical nodes

I have multiple web heads running a stack containing Apache/mod_php/Magento/MySQL and more. Every time I need to view logs I find myself jumping on multiple servers to view logs in different files ...
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3answers
2k views

mod_jk produces Error smh errno=13

I am trying to use mod_jk for load balancing. Loadbalancer 172.17.8.189 (HTTPD+mod_jk) Node1 172.17.8.193 (apache tomcat instance 1) Node2 172.17.8.196 (apache tomcat instance 2) I checked my tomcat ...
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1answer
482 views

Failover Cluster Migration Wizard (SQL Install Portion)

Have 5 SQL 2005 to 2008 R2 clustered instances. I've setup a new cluster to prepare to use the cluster migration wizard. As I understand it you have to install SQL before running the cluster migration ...
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349 views

Server 2012 cluster - SAN volume - failover not working

The following configuration is available: - 3 HP SAN disk Enclusores / 2 SAN controller; HSV200 (FC) - 2 HP Brocade SAN switches - 2 HP blade servers, each with a QLogic FC HBA QMH2462 - SAN volume is ...
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2answers
208 views

A roundrobin for incoming files

A bunch of new files with unique filenames regularly "appears"1 on one server. (Like hundreds GBs of new data daily, solution should be scalable to terabytes. Each file is several megabytes large, up ...
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2answers
40 views

2008 Clustered Services (SQL) to 2008 R2 Clustered Services

I've found plenty of articles for upgrading SQL in a clustered environment from SQL 2008 to SQL 2008 R2. However, I have not found much information in relation to migrating a current Server 2008 ...
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77 views

LDAP URL example: is it possible / correct to use only the domain without the hostname?

We have an application which connects to an Active Directory (MS) using LDAP protocol. We give usually the following parameters: ldapUrl = ldap://myserver.mydomain.ext:389 ldapBaseDn = ...
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2answers
60 views

Is it possible to have automatic failover of a windows service without windows clustering?

Due to a partial failure of our SAN we have switched our message queuing (Active MQ) from using network storage to using local storage. Because the secondary server is no longer sharing the same ...
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220 views

mod_jk tomcat error handling

I have a strange problem with my tomcat cluster. The cluster consists of 1 Apache with mod_jk and 6 Tomcat servers - each tomcat server is a own virtual machine. The cluster works as expected, ...
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243 views

glassfish cluster fail at start

I got a problem trying to set a cluster up. I'm gonna describe detailed configuration(since I couldn't find a cluster example made on two different pcs, all of them were made on one localhost): 3 ...
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2answers
42 views

Certificates for clusters

I have read the various threads regarding clusters (behind the load balancer) and certificates. I am trying to implement this in our company. Firstly Our compnay policy is not to allow exporting of ...
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371 views

Setting up computational cluster using infiniband fails

My task: I need to assemble computational cluster, consists of two nodes using infiniband technology. When I try to start mpirun ... for two nodes, the process hangs. If i try to use flag ...
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1answer
96 views

Mysql Cluster Sharding/partitioning [closed]

Ok so i have mysql cluster setup but what i need is say table assets to be split among the nodes, not replicated. as the purpose of me setting up the cluster was due to lack of hard drive space so how ...
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690 views

Confusion setting up a simple tomcat6 clustering on ubuntu 12.04 using mod_jk: status page won't show

am a little confused when setting up 2 tomcat6 instances cluster in a clean ubuntu server 12.04. i didn't install default tomcat6 i used tomcat6-user's tomcat6-instance-create to create 2 instances. ...
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1answer
167 views

Memcached distribution

I have a question about memcached distribution across nodes. We have 20 memcached nodes with 200GB memcached on each. Our apps are PHP apps. $memcache->setOption(Memcached::OPT_DISTRIBUTION, ...
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207 views

What is a logical web address, when using a loadbalancer for distributing load among clustered web applications?

In Oracle docs, I keep coming across the term 'Logical web address (LWA)', and this concept is especially useful while setting up a load balanced application. I couldn't find any documentation on ...
3
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1answer
2k views

HA mail server configuration

I have a mail domain and two servers (machines) with Centos 6.4 and public IP addresses. Postfix mail server and Dovecot IMAP/POP3 Server are installed on both. How would I set them up redundantly so ...
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1answer
86 views

In search of a distributed file-level filesystem [closed]

I'm looking for a distributed, fault-tolerant file-level (not block-level, preferably) filesystem for use in a small Linux-based HA cluster of sorts. The files that are stored will be fairly small ...
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146 views

How to bind CIFS server to virtual IP in Windows Server 2012?

I'm a unix guy who is new to clustering with Windows. I have two Windows 2012 servers that have the StorNext clustered filesystem mounted as drives on each. If I try to add the File Sharing role, I ...
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1answer
77 views

Windows or Linux cluster [closed]

I'm thinking on making a computing cluster at home to render things that I do in 3d programs like blender, maya and UDK. can I use a linux cluster enen though UDK only runs on on windows or am I ...
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58 views

How could I share data from a SAN?

I am considering deploying a SAN but I have found contradictory information. The thing is that I would like my cluster nodes to be able to read the same data from a unique source (I have a ...
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1answer
122 views

Red-Hat Cluster failover notification?

Is there anyway to get a notification / setup a notification mechanizem when the cluster fails over?
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1answer
125 views

mysql cluster .net client connection which host

I'm trying mysql cluster to use in a project for our customer. The configuration I setted up is the following: **Hardware S.O. equipment** Server1 - S.O. Windows 2008 R2 64bit Server2 - S.O. ...
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1answer
146 views

Does 'top' show memory / CPU usage of parallel processes on cluster?

Recently inherited a neglected cluster: I'm trying to do some sanity checks on it. Running a benchmark on node X and then running 'top' shows high cpu usage from mpi processes (as expected), but on ...