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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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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0answers
22 views

Could HAProxy disable the Apache Instance on the same node it is running?

I have a setup with three VMs that are running on a core i74xx. The machines form a LAMP cluster with HAProxy doing the loadbalancing. After running multiple load tests I found out, that throughput ...
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8answers
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alternative to Clusterssh for managing multiple SSH server

Is there any alternative to Clusterssh,pssh etc? to manage multiple ssh based servers through one interface? one weakness in Clusterssh is that my servers use key based authentication, with ...
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22 views

Windows 2012 R2 Cluster

This is my first time building a Failover Cluster. I run the validation and every time I get the following. "Failed to prepare storage for testing on node {SERVER NAME}: The remote procedure call ...
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2answers
270 views

RabbitMQ - How I do configure servers for zero-downtime upgrades?

Having read through the docs and RabbitMQ in Action, creating a RabbitMQ cluster seems straightforward enough, but upgrading or patching an existing RabbitMQ cluster seems to require the whole cluster ...
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clvmd problems during the RHEV cluster deployment

We are deploying Red Hat Enterprise Virtualization cluster and we faced a problem attempting to start clvmd service after the lvm partition creating. The following has been completed successfully: ...
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2answers
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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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1answer
13 views

How to sync clock and UIDs across different nodes of a cluster with Ubuntu?

I am new to cluster computing and Ubuntu. We have a computing cluster with 4 nodes (10 cores per node) with Ubuntu installed. The cluster is meant for scientific computing. To install a load ...
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1answer
22 views

Pool of machines without authentication?

I am working on a cluster of linux machines. What I need is for authentication to not be needed between the machines in this cluster, but required from outside. I have considered the idea of setting ...
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2answers
97 views

coordinating a script to run on only one of identical load-balanced servers

I have two identically configured CentOS 5 servers (possibly more in the future). I need to run a cron job on any one of them and that it'll run only on one of them. I know about RedHat Cluster Suite ...
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replacing eth1 for wifi ROCKS cluster [on hold]

the room where I will be setting up my rocks cluster does not have a ethernet port available, but there is private wifi that I can use. My question is can I use wifi instead of an ethernet connection ...
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1answer
1k 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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File system size different from LV size

I try to build a highly available Red Hat 6.6 cluster. Following is the procedure I followed to create each of 6 shared gfs2 file systems: I first created physical volumes using multipath friendly ...
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1answer
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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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1answer
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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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25 views

RedHat Cluster 6 node won't see shared volume group

I try to create a shared clvm volume group shared between 2 nodes of a Red Hat Cluster 6. Here is the procedure I followed: [root@node1 ~]# pvcreate /dev/mapper/mpathab [root@node1 ~]# vgcreate -c y ...
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Simultaneous server crash in fail over cluster

I have 2 servers in a failover cluster. The cluster defines a shared 'ClusterStorage' drive. The drive maps to a SAN device through iScsi. Recently, the 2 servers rebooted on their own at the same ...
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57 views

how to do automatic failover of mysql / galera cluster

I have two mysql/galera clusters of three nodes each (two + garb node). The clusters are in separate DC's (dc1 and dc2) The cross cluster replication happens between node1-dc1 and node1-dc2 I want ...
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12 views

Ceph remain in HEALTH_WARN after osd remove

I have a cluster of 3 servers with cepth storage over 9 disks (3 each server). One osd is going down/out and so I "remove" it, after that system start to rebalance data over the remainig osd but after ...
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2answers
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pcs status error httpd_monitor_5000 on server 'not running' (7):

Error Message Failed actions: httpd_monitor_5000 on abc-zabserver-b 'not running' (7): call=65, status=complete, last-rc-change='Wed Jul 15 21:44:43 2015', queued=0ms, exec=8ms pcs status ...
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2answers
381 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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3answers
49 views

Can we build a Hyper V failover cluster without a SAN or other shared storage?

I have a question about Hyper-V Failover Cluster. I have 2 server Hyper-V and want to use a failover cluster. As far as I know, I need a SAN server for that, so do we need it in here?
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1answer
16 views

Keepalived in the AWS autoscalling group

I want to deploy Keepalived in the AWS autoscalling group. The issue that Keepalived need to know ip address of the each node in the cluster, that is difficult in the elastic environment, where we ...
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1answer
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Cassandra 2.x - cluster does not rebalance after adding new nodes

I had 3 nodes, all with ~550GB, and added 4 more. I hoped that data would migrate on its own from old servers to new ones. Unfortunately after one day, data seems to stay in old places. In parallel, ...
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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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Is it a good idea to store Docker volumes in glusterfs?

I am currently thinking about migrating some of our servers and apps to a coreos enviroment. One of the problems I see here is the management of persistent data as coreos does not handle Docker ...
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1answer
84 views

MariaDB Galera Deployment

I am looking to experiment with MariaDB 10 Galera Cluster. I am looking for highly available, scalable and reliable architecture. Basically I am curious what would be the better architecture and would ...
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2answers
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nginx automatic failover load balancing

I'm using nginx and NginxHttpUpstreamModule for loadbalancing. My config is very simple: upstream lb { server 127.0.0.1:8081; server 127.0.0.1:8082; } server { listen 89; ...
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Windows Cluster An error was encountered while determining shared storage

Our SAN manager has added a new disk for our cluster. this is a new 6TB disk that will be used for backup and will be part of a file share. I have put the disk online, initialized it and assigned the ...
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1answer
24 views

Galera cluster implementation questions

I've just successfully created my first Galera cluster using MariaDB 10.0.20 between three servers. I have a few questions regarding my implementation: 1. what will happen if one server becomes ...
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1answer
12 views

SQL alwaysON and WSFC

I have a WSFC configured on 2 (hardware)nodes with SQL AlwaysOn group. The problem is, if the node Where I have created the cluster goes down the cluster is not available for second node and here ...
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Is it possible to create NUMA cluster containing 2-3x Dell / HP servers for SQL Server 2008 R2?

I want to create cluster of servers working at the same time on 1 query. Currently my server for some queries is providing unacceptable result time (server is providing data to the request for my ...
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Why configure cluster nodes to reboot when out of memory?

I have access to a research HPC cluster which is configured so that if your job tries to use more memory than the node has available the node crashes and automatically reboots. This appears to be ...
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2answers
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why would adding a crossover private nic cause IP address resource fail?

2 node Win 2008 R2 quorum cluster Configured 192.168.0.0/24 "public network" Configured cluster MSDTC Installed SQL 2008 R2 cluster instance Manually failover groups - OK Reboot server w/o failing ...
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1answer
39 views

What distributed FS, with small files read / write workload perform better?

I have 2 machines sharing storage via iscsi (multipath), soon we add another one, this machines are Web app servers that read small files on shared storage ( < 256kB), and write them back. so we ...
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1answer
21 views

SQL clustering without WSFC (Windows Server Failover Clustering)

Is it possible to cluster, or make SQL "highly available" without having to pay the huge enterprise prices? By the looks of it, any type of SQL clustering requires enterprise edition Windows Server. ...
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1answer
49 views

Can you list a Datastore Cluster's sDRS Schedule via PowerCLI?

We have a lot of datastore clusters, most if not all are supposed to have sDRS schedules applied to stop them moving VMs at busy periods. Obviously we could trawl through them manually to check if ...
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1answer
44 views

Multiple vCenter Services for redundancy

I've been reading up on linked mode, but this only applies to the management on multiple clusters from a single vCenter via linking other vCenter's into it. My question is - can you have two servers ...
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mysql galera 2-way cross-cluster replication

Scenario and setup Two mysql galera clusters in two datacenters with 2-way multi-master replication Each cluster has 3 nodes: 2 full nodes and 1 garbd node Example host names: dc1-sql1 --> ...
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Choice of distributed filesystem for intensive reads and writes

I have a series of servers (HP ProLiant, 34 servers) each of which with 500 G of hard drive space. These servers are part of a computational cluster which runs processes that roughly fall into two ...
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Clustering filesystem for small files

I'm looking for a distributed filesystem which I could use for storing lots of small files (<1MB usually). What I want to get is: 2 servers which have the fs mounted themselves and mirror the ...
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3answers
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How does HA / failover work?

Let's say we have ten servers, each one has a copy of stateless application. user enters address in a browser / client program. dns server returns a list of ip (however many people say that dns ...
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1answer
24 views

Pacemaker and Stonith : passive node won't bring up resources

I'm working with Pacemaker and Stonith for High-Availability with a 2-node cluster (nodes called here A and B). Both nodes have one IPMI as fence device. The deal is : A is currently running ...
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Pacemaker ocf:heartbeat:IPaddr on different subnets

I'm trying to add a Pacemaker virtual IP address; with it, the gateway, and the two VMs it serves on different subnets. I've only done this before with all IPs on the same subnet, and I need some ...
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1answer
75 views

MariaDB Galera Cluster, Force Sync

I have three servers in a multi-master Galera cluster. I've imported some old databases recently, and noticed that the tables were being created across all three, but the data wasn't being ...
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1answer
20 views

How to manage access to nodes in a cluster?

I am about to set up a server cluster for our company's web applications. At the beginning there will be 3 hardware servers in Proxmox HA setup in a remote datacenter running about 20-30 VMs all ...
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1answer
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What happens if fleet can not meet the requirements for an unit

Take a look at the following scenario: I have a CoreOS / fleet cluster with 4 nodes. There are 4 apache units with the following line Conflicts=apache@%i.service One machine goes down. Fleet ...
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1answer
28 views

Cassandra NetworkTopologyStrategy

I would like to configure the following multi-datacenter Cassandra cluster: DC-EUROPE has 3 Cassandra nodes (1.1.1.1, 1.1.1.2, 1.1.1.3) DC-ASIA has 3 Cassandra nodes (2.2.2.1, 2.2.2.2, 2.2.2.3) Each ...
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7answers
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How to reserve complete nodes on Sun Grid Engine?

How do you use SGE to reserve complete nodes on a cluster? I don't want 2 processors from one machine, 3 processors from another, and so on. I have a quadcore cluster and I want to reserve 4 ...
3
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1answer
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NetApp cluster fail to start

I have a big problem with my FAS2020 (configured as iScsi storage for 2 esxi 4 server). I couldn't ping the 2 ip address of the FAS so I connect by the serial port with putty for monitoring the boot ...