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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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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High Availability Options for MSMQ

We plan to develop a highly available system based on Microsoft Message Queuing (MSMQ). Currently we are collecting high availability options for MSMQ. We plan to use Windows Server 2008R2 as the ...
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What are the exact storage requirements for an AlwaysOn implementation?

We're investigating implementation options for SQL Server AlwaysOn. AlwaysOn is dependant on Windows Clustering, and I have read several articles that state shared storage is no longer a requirement ...
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High Availability and Load Balancing for MySQL and Jetty

I'm about to deploy two distinct systems: A MySQL cluster and a cluster of Jetty web-servers. 1. SOFTWARE I can get more linux servers for the HA/LB, but which software should I use? I'm with CentOS....
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528 views

Heartbeat is giving me a heartache

I have 2 Ubuntu 11.04 VM's on which i have installed Heartbeat + apache2 to achieve a "high availability" setup. Heartbeat is up and running on both but im not able to ping the Virtual IP (cluster ip) ...
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653 views

Solution for two-way file-system transparent solution

I need to implement some sort of HA setup where 2 servers need to be able to always be in sync, no matter on which one you write on. The DB part can be covered by a master-master replication setup. ...
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store high amount of photos (150 million) and make available for web [closed]

For a actual project I must setup a high-available storage server who can store and publish (http) 150 million photos in 7 sizes means total 1050 million files. For every photo we need total 200 KB ...
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779 views

What are the advantages of async. database mirroring over transaction replication?

I've primarily a developer, but our organization is small, so I have been tasked with developing a HA strategy for our SQL servers. Currently, I manage our transactional replication to two additional ...
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High Availability and Load Balancing with Debian 5.0 (Lenny)

Suppose I have two Debian 5.0 servers and a generic session-based DB-driven website is running on them. Assume that the two DB instances are already clustered. Each server has its own internal IP ...
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395 views

Firewall that supports HighAvailability and Spanning Tree

I'm looking for a firewall appliance that supports high availability and spanning tree. I have two ha-cluster nodes and I'd like to protect them with a firewall. To avoid a single point of failure, I'...
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67 views

Installing two versions of MSSQL on a production server?

We've just provisioned a second dedicated server so we can use database mirroring for high availability. The existing server uses MSSQL Express 2005. We have MSSQL Web 2008 and want to minimise the ...
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835 views

vSphere HA - Dealing with storage hba/link failure?

I'm looking at putting in a small cluster spanning two locations on the same campus. The vSphere hosts in each location would have a vSwitch connected to the production LAN, and I'd also be using a ...
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580 views

Does order of servers in nginx config matter?

I have a custom tool which generates a part of nginx config in the following form, for example: upstream backend { ip_hash; server server1:8080; server server2:8080; server localhost:8080 ...
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241 views

What database is easy to maintain and manage in a cluster?

I'm looking for a database (DBMS) that is easy to scale out. I would like to have high availability so I need a multi-master cluster, where the data is replicated to two or more physical computers. I ...
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71 views

connect to my website from multiple external remote sites

I remember seeing a website where I could type in my home page url, and then get a list of a bunch of servers that connected to my url in real time, from all over the world. the report would show ...
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2answers
444 views

tools for geographical redundancy

I'm writing a spec for a high availability application. I need a low budget solution to be able to failover between two data centers. Replicating databases and content I'll be able to manage solutions ...
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317 views

MySQL Proxies

In a similar line to... http://serverfault.com/questions/35899/mysql-5-1-replication-topologies-multi-master What I'd like to know is whether there are any really good proxies for MySQL out there? ...
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116 views

How does systemd decide if a service is ok or not

This question is related to: reliable systemd service for autossh I have a service which uses type=simple. Here the systemd docs: Type=simple (default): systemd considers the service to be ...
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Get IP of node running a specific resource when demoting master nodes to slaves

Setup I am setting up a HA cluster for a web application with 2 nodes (2 physical servers): node1 (current master node) node2 (current slave node) Using Corosync & Pacemaker I was able to ...
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545 views

Configure HA Proxy between Apache and Tomcat servers

Want to configure HA Proxy with my existing structure. Currently I have Apache->Tomcat server. This I want to change to Apache->HA Proxy->Tomcat Server. HA I have configured for Http request. But my ...
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new hyper V High Avaliability setup and SMB 3.0 storage

I am looking at building an new 2012 R2 with Hyper V setup, everything has to be HP hardware. 2x HyperV 2012 R2 servers running 20-30 VMs. These will be dual 6 core xeons with 128gb of ram. 2x 2012 ...
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616 views

Simple redundancy setup using two servers in two different datacenters? [closed]

Scope of the question This question is solely about getting a client requesting a domain: example.com to one of the two available servers. How it is handled from there on, is another problem to solve ...
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617 views

Linux HA Heartbeat Virtual IP Switching with domain name linked to it

I have heartbeat set up on two servers like so: Master: 10.15.1.50 Backup: 10.15.1.51 (Virtual IP: 10.15.1.52) So, the master always has 10.15.1.52 as well, but if it goes down, the backup will ...
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Suggestions on providing HA access to an external (fibre) RAID subsystem

We are looking at upgrading our storage capacity with an external RAID subsystem that has redundant (2) fibre controllers, each controller has 4 x 8 Gbps fibre ports. I would like to make access to ...
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141 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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146 views

Swap DNS entry on failure

I'm building an application that requires high-availability. We currently run: 4 webservers, 2 varnish servers (both with Pound for SSL proxy), 3 Cassandra nodes. The varnish servers are used as ...
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Availability & Scaling : Three Tier or Two Tier

I began working on a three -Physical- tier website (UI:MVC / Application:REST / DB), I've always considered that three tier is more scalable than two (taboo for high traffic websites), but lately i ...
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heartbeat: Bad nodename in /etc/ha.d//haresources [node1]

I'm trying to start heartbeat on Ubuntu 10.04 with service heartbeat start, but getting the following errors: heartbeat[24829]: 2011/11/22_19:31:07 ERROR: Bad nodename in /etc/ha.d//haresources [...
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1answer
331 views

Change hostname on linux ha failover case

I have configured two machines to do a warm standby so that machine 2 can take the ip of machine 1 if that should fail and become its replacement. sadly, thats not enough, i need to change the ...
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122 views

Veritas Cluster Server for HA for regular user processes

In the past I have used Veritas Cluster Server for HA clusters of Sybase and other databases at large financial institutions. Now I am going to have locally written processes that could benefit from ...
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Exchange & MS SQL high availability

Could anyone suggest how high availability can be achieved for MS exchange and for MS SQL server between two Data centres when one server each is located in a data centre? Users from a siteA connected ...
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2answers
879 views

load balancing, high availability for webapp setup

We have build a special interest social network and need to setup now the proper server setup for the webapp servers. We have for the webapp 5 physical server available (2xE5645 CPU, 24 GB Ram, RAID, ...
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Implementation of a fully-redundant, high-available iscsi SAN (consisting of n machines) in conjunction with clustered filesystem

a short example of how the infrastructure may look like: 4 servers act as iscsi targets and expose 1x2TB each (every of those servers has a raid10 for the storage, thus 2TB of usable capacity) n ...
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Unexpected start of already-primary server processes when heartbeat on secondary is stopped

I've got an active-passive Heartbeat cluster with Apache, MySQL, ActiveMQ and DRBD. Today, I wanted to perform hardware-maintenance on the secondary node (node04), so I stopped the heartbeat service ...
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crm_mon -E does not run the external-agent on Debian Jessie

Setup I'm currently having a working 2-nodes HA cluster using Pacemaker+Corosync. My nodes are running on Debian 8 (Jessie). Now I would be able to get notified when changes occur in the cluster (...
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HAProxy failing at random times (backend has no server available!)

I have a CentOS 7.1 (x64) droplet configured to load balance between 2 apache/php servers. I have it working perfectly, but randomly throughout the day it reports the following: haproxy[12947]: ...
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Loadbalancing and HA with SolrCloud?

I have a LAMP Application running with solr 3.x on one server for several years now. Now I am migrating due to heavy load to a setup with two dedicated machines where all services are loadbalanced via ...
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SLES 12 High Availability Cluster - scsi persistant reservation fencing

I'm trialling SLES 12 w/ HAE to run a Fileserver cluster consisting of two nodes. Idea was to use SCSI persistant reservation as a fencing method using the fence_scsi script from stonith fence agents. ...
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186 views

How to let Corosync / pcs control nginx?

Folks, I'm trying to replace a single aging load balancer with multiple virtual machines running nginx. However after I got centos 7 and nginx installed I realized that heartbeat has been deprecated....
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Is it possible to prevent pcs/dlm/crm from fencing the node when it fails?

Is it possible to prevent pcs/dlm/crm from fencing the node when it fails? I use cluster only to be able to build GFS2 storage, and there's my own way of avoiding split-brain. So I do not need things ...
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572 views

DRBD + corosync + pacemaker - Servers won't connect after failover

I got 2 servers configured with drbd, corosync with pacemaker. It is all working fine, primary server gets secondary if it fails, and secondary gets primary. But if the 1st server comes up again ...
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282 views

Clustering with Jboss EAP and Load balancing with Haproxy

I'm doing load balancing with HAProxy and use JBoss EAP as application servers. The Haproxy server is configured to route incoming requests to the application servers. How can I integrate Jboss EAP ...
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Is it at all commonplace to make service available via the same host as its redundancy, just different ports? [closed]

I am writing software that allows for the configuration of parameters for authentication with a Primary and Secondary RADIUS server. Server administrators, in your experience, is it common or not for ...
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51 views

Website failover across internet connections

Requirement For a network having 4 static IP internet leased line connections linked to hosting a website. What are the current strategies one can apply to ensure high availability in case of ...
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1answer
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NFS failover fails with stale file handles while migrating resources

Running into a bit of a problem here , I set up two servers ( Centos 6 ) with Glusterfs and a shared directory between them, I have moved the nfs directory to the shared Gluster folder and have ...
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Multiple httpd with JBoss cluster: provide httpd HA

I have a working configuration like this: +-----+ +-----+ +-----+ +-----+ | i1 | | i2 | | i3 | ... | in | JBoss Cluster +--+--+ +--+--+ +--+--+ +--+--+ | |...
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TeamCity (or Jenkins) with Cluster/Replicated servers

We use Team City 7 for Continuous Intergration. Sometimes I need to bring down the server for maintenance which stirs up complaints. Is anyone using a cluster for these types of servers where there ...
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LVM DRBD Shared between nodes proxmox

Context : I have proxmox cluster with the volume group shared with drbd for the VM - KVM. I have a problem with drbd. Indeed, when a node disconnect, the associate link between the differents nodes ...
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Solr on a two node Jboss cluster

Are there any issues with deploying Solr on two node jboss cluster with the index shared on a NFS mount point? We would like to do this for high-availability across data centers.
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Clustered file systems as XenServer storage

I want to use shared storage for a XenServer environment with 4 host servers which are running various VMs under XenServer. Planning to use 2 extra servers as storage with high availability of some ...