High availability is an architectural consideration often involving degrees of redundancy to insure availability in case of system or component failure.

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How to setup a simple Ubuntu Server Tomcat cluster on VirtualBox for testing? [closed]

I am looking for the step by step instructions to setup at least two simple Ubuntu Virtual Core 12.10 Server VMs on Oracle VirtualBox under Windows 7 64bit. The test setup would be: Apache HTTP ...
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Oracle replication A->B and B<-A?

If you have two unrelated Oracle databases on separate servers, can you replicate A to B and B to A so both servers have a copy of both db's? Idea is for DR "on the cheap" without buying more Oracle ...
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137 views

Multi-Master Replication Manager for MySQL With Semi-Synchronous Replication

I'm attempting to set up Mysql nodes in active/passive HA setup with a virtual ip managed by HAproxy + Heartbeat/Corosync with MyISAM support (which excludes Galera/Percona) Does Multi-Master ...
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35 views

Can I use Veritias Storage Manager to provide HA storage using server-local storage?

I have a need to provide an high-availability ftp/http file repository. Upload will happne to one server, but the uploaded file must be immediately visisble on all other servers I can handle the ...
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107 views

Monit server went down

One of our developers needs some sort of notification in order to know whether the application is running smoothly or not.And We already decided that we will implement monit in order to get this ...
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159 views

ssh host key management between ha hosts

We have a setup with 2 Redhat-based servers which are both ha hosts behind a virtual ip. 192.168.0.3 dataserver (virtual ip) 192.168.0.1 dataserver_ha1 (physical server) 192.168.0.2 dataserver_ha2 ...
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121 views

Why state is needed for keepalived

From the doc ! MASTER and BACKUP state are determined by the priority ! even if you specify MASTER as the state, the state will ! be voted on by priority (so if your state is MASTER but your ! ...
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Windows Server 2012: Possible to have High Availability and reliability without needing a SAN, but connecting servers together?

I have some questions below -- tried to word them the best I could. If you downvote my post, please make a comment explaining why you downvoted so that I can try to do better when I post in the ...
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247 views

Is it not possible to use keepalived in EC2

The problem is two of my EC2 instances (ha proxy) need to bind a single virtual IP if I want to use keepalived, but they are not possible in EC2 as only a single instance can use a elastic IP at a ...
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How does a SQL Server Availability Group decide on which secondary will become the new primary when an automatic failover is triggered?

How does a SQL Server Availability Group with multiple synchronous-commit secondary replicas decide on which secondary replica will become the new primary when an automatic failover is triggered? ...
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Cheapest High Available Web Server [closed]

I would like to create a high-available setup (e.g. a small cluster) for a webserver, i.e. it will run Apache, PHP and MySQL. There will be between 2-8 small websites running with only very little ...
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Options for Multisite High Availability with Puppet

I maintain two datacenters, and as more of our important infrastructure starts to get controlled via puppet, it is important the the puppet master work at the second site should our primary site fail. ...
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4answers
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Looking for a solid redirection infrastructre [closed]

We have critical servers (webservers and databases) that are fully replicated, except for the reverse proxy that we use to hide the internal stuff. This proxy is acting like a router that filters and ...
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Should an HA failover occur in this scenario?

I'm running vSphere 5 in an HA cluster across two hosts (vsphereA and vsphereB). I have the HA cluster configured for host monitoring and datastore heartbeat monitoring with admission control disabled ...
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149 views

High availability setup with 2 tomcat servers in Windows

I am trying to set up a high availability setup(not load balancing, only HA) with 2 tomcat servers. When I google for information, I get tons of links with apache+HAProxy+keepalived setup for linux ...
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297 views

HAProxy — pause/queue all traffic without losing requests

I basically have the same problem as mentioned in this thread -- I would like to temporarily suspend all requests to all servers of a certain backend, so that I can upgrade the backend and the ...
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2answers
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Alternative to GlusterFS [closed]

I need to create a redunant 2-linux machines configuration so that the files on server1:/dir are in sync with the files on server2:/dir I managed to configure GlusterFs to do this but while it works ...
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How to handle server failure in an n-tier architecture?

Imagine I have an n-tier architecture in an auto-scaled cloud environment with say: a load balancer in a failover pair reverse proxy tier web app tier db tier Each tier needs to connect to the ...
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339 views

2 servers, high availability and faster response

I recently bought a second webserver because I worry about hardware failure of my old server. Now that I have that second server I wish to do a little more then just have one server standby and ...
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481 views

Keepalived not honoring nopreempt

I'm using Keepalived to manage two Redis instances in a master/slave configuration. I'm experiencing a situation where, if Keepalived is terminated on the Master box (the one with the higher ...
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135 views

Budget High Availability configuration for Linux (Debian) boxes [closed]

I try to set up a (pretty) high availability solution for a service that I run on Linux machines and here's what I come up with: - one front end server used for balancing. IT should have haproxy ...
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2answers
319 views

Drbd Primary/Primary + iSCSI: accessing to different files avoids split brain?

I have a question / curiosity about split-brain on a Drbd Primary/Primary configuration. Supposing two nodes (hosts), host1 and host2 configured with Drbd Primary/Primary and two different shares ...
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194 views

Server Clustering on differen OS : CentOs and Debian [closed]

I have two dedicated servers in two different locations. One at USA (Based on CentOS), another at Asia (Based on Debian). Need to implement High Availability HTTP Clustering. The main complexity is ...
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Stratus Servers vs Virtualised Machines as a High Availability Solution [closed]

I've been asked to do this as a presentation, but to be honest, either I've totally missed the point or am I being asked to compare an actual company i.e. Stratus against the concept of virtualising ...
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If DNS Failover is not recommended, what is?

As a followup question to his very popular question: Why is DNS failover not recommended?, I think it was agreed that DNS failover is not 100% reliable due to caching. However the highest voted ...
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Service haproxy error

I want to configure Haproxy for outgoing mail load balancing. my configuration file /etc/haproxy.cfg is. global maxconn 4096 # Total Max Connections. This is dependent on ulimit ...
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167 views

Risks of Network Partitioning When a Split Brain Creates a Security Flaw

I'm looking to create a high-availability, scalable networking solution by using a distributed system of data. A node here, describes a network that has control over one copy of the data. These nodes ...
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1answer
475 views

MySQL HA and Magento DB

Is it possible to use MySQL cluster for Magento DB? I have Web app developed in Magento E-commerce platform and I want to make DB highly available using the MySQL cluster. Magento supports only InnoDB ...
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unmount failure because of process in D stat

Please suggest me how I can create a process in D (uninterruptable sleep) stat on mirror disk. Actually there is some bug in other code, that process some times create a process with D stat on MD and ...
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MySQL HA Solutions

I am evaluating the options to build MySQL HA and found the below solutions Percona XtraDB Cluster, Tungsten Replicator, and MySQL Cluster. Could you please help me to choose the best one with ...
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keepalived doesn't listen on virtual IP

I'm learning to use keepalived; for now within a single machine - just to make sure the forwarding works. I've started a mock webserver listening on 192.168.56.200:8080. It just replies with the ...
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43 views

Setup a constant web application availability on Windows Server

I am a part of a team that is building an ASP.NET web system. We need to guarantee, that when the main hosting server with IIS is being updated, web site visitors get the special message that the ...
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254 views

Highly available and scalable SQL Servers with read-only databases?

I've been thinking about building a website which could potentially get a lot of traffic. It would be a research site of sorts with wiki capabilities. So users would be able to edit information on ...
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430 views

SQL Server 2012 Mirroring / AlwaysOn - need for SAN?

There appears to be a great deal of conflicting information about whether or not SAN is required for a Sql Server 2012 Mirroring setup. I currently have an Active-Passive-Witness SQL 2008R2 setup ...
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Fence node in apache traffic server

I'm currently looking into Apache Traffic Server as a tool for providing better availability of web services. But looking at the manual I can't see any reference to how I can pro-actively fence a ...
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101 views

Failover solution for web servers

I'm looking for some failover solution between two web servers. The web servers (CentOS+Nginx) are running on KVM virtualization platform. I was testing RedHat high availability cluster but I've ...
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36 views

Heartbeat external plugin configuration format

I have developed an external Heartbeat v1 plugin, which expects its configuration by means of environment variables. AFAIK, this is what Heartbeat provides when configuring the plugin using the ...
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How stable is the VMWare vCenter Server OVF and is there a better way to get HA features?

I am considering pruchasing Vsphere solely for the HA feature, however, in order to do this, I will also need vCenter Server. I am not keen on purchasing a copy of Windows especially for this and ...
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Can not switch drbd to secondary

I'm running drbd83 with ocfs2 in centos 5 and planning to use packemaker with them. Afer some time, I'm facing drbd split brain problem. version: 8.3.13 (api:88/proto:86-96) GIT-hash: ...
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440 views

How to setup heartbeat for IP fail over on SSH failure

I wonder if anyone can help me, I am trying to setup heartbeat on a redhat 5 to failover an IP address when ssh stops responding on a server. So basically you ssh to a VIP and then get put through ...
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MySQL: Pacemaker cannot start the failed master as a new slave?

pacemaker-1.0.12-1 corosync-1.2.7-1.1 I'm going to setup failover for MySQL replication (1 master and 1 slave) follow this guide: ...
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294 views

IP failover on different subnets

I have two real servers, on different subnets, each one with a permanent IP, and with a failover IP that can be used by either server. The hoster provides an API with which I can assign the failover ...
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What are the ways to build a failover cluster?

I have a task where I need to build a failover cluster in two cases: first with servers on Red Hat Enterprise 5.1 and second with SUSE Linux Enterprise 11 SP1. Both cases have SAN. I know there are ...
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187 views

Which routers support bgp and would work well for simple dual office redundancy [closed]

We have two sites that each have an internet connection and have a dedicated dark fibre between them. Each site has it's own IP space and we have an AS number. We're looking to be resilient to failure ...
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239 views

SBD killing both cluster nodes when there are even small SAN network problems

I am having problems with stonith SBD in a openais-based cluster. Some background: The active/passive cluster has two nodes, node1 and node2. They are configured to provide an NFS service to users. ...
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1answer
419 views

Using LVS (Linux Virtual Server) for doing DNS HA

I have been trying to create an LVS DNS HA using CentOS 6.x: Piranha GUI to configure the DNS Pulse is the HA heart of CentOS LB IPTables to configure marks on the packets since DNS uses TCP and UDP ...
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146 views

Improve automatic failover scenarios in SQL Server 2008

We have SQL Server 2008 set up in with a principal, mirror and monitor server, the mirror is synchronized and set to automatic failover. We recently saw a situation where we ran out of space on the ...
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How many mongod instances should I run with a 2 server replicaset setup?

Currently I've got server A and server B running with the following mongod instances: Server A mongod server (usually PRIMARY) mongod arbiter Server B mongod server (usually SECONDARY) When ...
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Simple IP load balancer for web service that runs on Windows XP or Windows 7 Professional?

I've a closed code application that needs to connect to a web service that needs to run on XPs or Windows 7 (desktop). The application can only connect to a single IP address. The application is low ...
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3answers
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Storage cluster for inexperienced admin

I'm a relatively inexperienced server admin who primarily works with Windows and a little bit of Linux. I'm the only admin of a small organization. I'm looking for a way to have a high-availability ...