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 2012 AlwaysOn Availability Groups Failover Successfully But Application Complains About Login Failed for User

I am trying to get SQL 2012 AlwaysOn Availability Groups working for an application. The cluster has 2 SQL nodes and 1 witness server. Everything appears to be failing over successfully when I do ...
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3answers
146 views

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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2answers
590 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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0answers
648 views

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 help....
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1answer
474 views

HAproxy mysql failover

I try to set up a HA cluster with Percona xtraDB Cluster for MySQL replication and HAproxy for load balancing. HAproxy works really good with apache, when apache crash or if it's not responding, ...
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1answer
27 views

i need redis high availability statistics

does anyone have any real life statistics on how long they can keep a Redis instance up and running for? I know I can get Redis Sentinel to give me fail over functionality but what is should be my ...
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1answer
3k views

OpenVPN timeout to reconnect on fail takes a long time

I'm trying to create a high-availability environment for my OpenVPN servers. I do this by having two identical VPN servers and in my client config specify multiple remote's: # The hostname/IP and ...
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189 views

Why both nodes in OCFS2 cluster keep rebooting?

We created an OCSFS2 cluster by using SUSE Linux High Availability Extensions on SLES SP3. The cluster nodes are two Apache servers which share one disk. We have stonith enabled and SBD daemon. It ...
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2answers
287 views

Can't change source IP address (to floating ip) for udp outgoing packages

I'm having trouble getting a cluster to work using pacemaker and corosync. Here is my hardware configuration: Network: 192.168.3.0/255.255.255.0 Gateway: 192.168.3.1 node1 (Ubuntu Server 12.04 x64) ...
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1answer
258 views

Pacemaker ClusterIP stops working after 15 minutes but is still running

I am running Corosync and Pacemaker via a cman stack, in an active-active setup delivering web pages, and I've hit a brick wall. I'm using the IPaddr2 resource agent to have an IP that is used ...
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0answers
121 views

JBoss EAP 6.2 high availability without HTTP server

i'm looking for some solution to make a Jboss Cluster ( 2 nodes ) in H.A. ( 1 live, 1 backup) but i don't want to use a third element ( machine, service or whatever ). Most configuration I found uses ...
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3answers
687 views

What is the definition of High Availability? [closed]

As far as my understanding goes the availability of a service or system is defined as: (Time resource was available - Time resource was unavailable) / Total Time My questions are: Is describing ...
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1answer
432 views

Zabbix web interface says Zabbix server is offline when failing over to passive node

Two Zabbix 2.4 servers using CentOS 6.6 with an external MySQL DB, both servers are configured to connect to this DB when they are running. I followed a combination of Zabbit High Availability guide ...
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1answer
390 views

Single Nginx Load Balancer for 2 different clusters (web, api)

I was wondering if it was possible to use a single Nginx server to load balance my web servers and api servers if both are using port 80. In this setup there would be 5 servers, 1 Nginx and 4 Apache ...
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2answers
468 views

POST of large file is timing out, when running through ARR

When POST'ing a large file through ARR, the request times out after 120 seconds. The client recieves error code 502 Bad Gateway. I have configured the "proxy timeout" of the web farm to be 600 seconds....
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65 views

Load balance and contingency server

everyone. I'm having trouble setting up a load balancing/contingency server. My scenario: I have 2 servers (Windows 2012 R2 machines) to run an application in ASP.Net/C#. My problem: Would I like to ...
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3answers
770 views

Replicating a linux web server

I'm planning on replicating a web server for high availability purposes. The server is running as a Ubuntu 15.04 virtual machine in Hyper-V and has MariaDB 10.0, Apache 2.4 and PHP-FPM 5.6 installed. ...
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1answer
365 views

How can I deal with failures when connecting to a MySQL cluster?

Our company has created two MySQL servers that are kept in synch using a master-master strategy. The two-machine cluster is managed using crmsh. This is only a high-availability cluster, meaning that ...
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226 views

Solving an asymetric HA Firewall/router

I have an old Linux HA firewall/router setup that never quite worked. As it was never quite put into true production (just testing and demo's), I always had to have one firewall shutdown to make it ...
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1answer
275 views

Why Failover instead of Load Balancing for HA

From my understanding with failover clustering, only one machine is actually working, which means the other one(s) are sitting idle. So why would one use failover clustering instead of using a load ...
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1answer
148 views

Creating High Availability Netflow Collector

I'm currently working on replacing our existing Netflow collector that is EOL with a new one. The goal is to support around 4 million flows/minute and have HA capabilities. Below is my initial thought:...
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1answer
82 views

How to setup user accounts on a secondary server in High Availability?

Working with two Microsoft SQL 2012 servers in Always On High Availability configuration running on Windows Server 2012 R2. Setup works well and failover is almost flawless. However, the software ...
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2answers
173 views

Restarting failed hosts on VMware vSphere ESXi

When a cluster is configured for High Availability (HA), VMs can be restarted onto an alternate host when the its host has failed. However, I am wondering: if the host has failed, is there a means ...
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609 views

corosync is not in sync

Could you please help out show me how to form a cluster? corosync & pacemaker are used. two nodes rac0 ip 192.168.0.140 & rac1 ip 192.168.0.142 They are not shown in each other. They are ...
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82 views

Run generic Windows Service with affinity for the Primary Replica of an SQL Server AlwaysOn Availability Group

Is it possible to configure a generic Windows service in a Windows Server Failover Cluster such that the service always runs on the same machine as the Primary Replica (read/write) of an SQL Server ...
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142 views

Convert existing servers to a failover cluster

We have ourselves quite a quandary right now. For some time, we've been planning on setting up a failover cluster for our existing servers. The plan so far has been to set up a 2-node GlusterFS ...
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1answer
436 views

Keepalived + Haproxy performance, apache or nginx? [duplicate]

I have a question about Keepalived + Haproxy. At work I am assigned to deploy a redundant web server with Keepalived and Haproxy. Our setup at the moment is as follows: Apache (as load balancer) + ...
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192 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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0answers
338 views

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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1answer
306 views

VMware High Availability questions

I can't seem to find the answers to these questions within the vSphere 5 Documentation center, so please share if you are aware of any aspects of these questions. What happens to the failed VM that ...
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56 views

Apache mod_jk LB synchronization server startup + application startup time

after a long search I can´t found a solution or path to solve my problem with synchronization startup of Apache and Backend servers. I have a Apache2 using a LoadBalancer with mod_jk that balance ...
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1answer
32 views

vmWare HA Admission Control configuration

In an HA cluster of 5 hosts (100GB memory) if Admission control is enabled and %age cluster failover option is set at 25 % (lets consider only for memory ie. 125 GB), and if one host fails then the ...
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1answer
371 views

Active/Passive Reverse Proxy with nginx

I have two Websocket servers which working with Zookeeper & Curator as Active/Passive, if one server fails then second backend comes alive. I configured it the following way: upstream backend { ...
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62 views

Strange haproxy behaviour

So I'm trying to set up a dual site haproxy (1.5.10) on Ubuntu 14.04. http://i.stack.imgur.com/EtdYo.png When I do service heartbeat restart on eartha, both machines go green briefly; then earthb ...
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2answers
194 views

Which method can I use to automate DNS-failover with monitoring?

We're operating multiple redundant servers across the world for latency reasons. Currently if one site goes down, our only way to let another site take over that region is through DNS. We would like ...
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1answer
153 views

Building the infrastructure to support a web application

I am building infrastructure to support a web application. I think I have a decent idea of what the infrastructure should look like, here's what I have: 2 x 16GB, 4-Core HAProxy servers for load ...
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142 views

Failover pacemaker cluster, packet loss monitor

It's issue is continued from this. So, i have two test servers in one vlan. srv1 eth1 10.10.10.11 eth2 10.20.10.11 srv2 eth1 10.10.10.12 eth2 10.20.10.12 Cluster VIP - 10.10.10.100 ...
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278 views

Configuring Proxmox Cluster Storage

We are configuring proxmox on our servers at two locations each location has; 1 x hp c7000 enclosures with 16 blades 1 x hp proliant dl585 We also plan to add a 24TB SAN to each location. We are ...
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1answer
887 views

Optimal configuration with Synology as HA iSCSI backend for vSphere

I'm looking into purchasing a new storage backend for our VMware vSphere Essentials package. We have 3 ESXi hosts, currently mainly using DAS. The goal is to upgrade to Essentials Plus this year, to ...
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1answer
224 views

ipt_CLUSTERIP: unknown protocol 1

I am trying to create a web cluster with two load balancers and a single public ip address The command I use is the following: iptables -I INPUT -d $CLUSTERIP -i $WAN_IF -j CLUSTERIP --new --...
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0answers
598 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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1answer
359 views

keepalived multiple instances

I have two application servers running keepalived that are both using keepalived on the same network. I keep seeing Jan 8 11:49:01 <server> Keepalived_vrrp[13764]: bogus VRRP packet received on ...
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291 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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1answer
392 views

Simple file share failover

I have a simple file share on Windows 2012 R2 server which I would like to be high available. I created failover cluster, but I'm not able to set up FileServer service as there is no shared storage. ...
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1answer
270 views

How to AVOID getting caught in a DDOS meant for someone else (not prevent)?

So we have a load balancer and all that jazz set up with Rackspace. However, guess what, our clients' websites were down again today. It seems that Rackspace should have their load-balancer ...
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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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1answer
260 views

How to reconnect to the backend with HAProxy

I'm new in working with HAProxy. I couldn't figure out how to make HAProxy to reconnect to backend that was down and started up back again. I have a configuration of two backend servers. When they ...
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1answer
395 views

Monitoring pacemaker with url trigger external agent

I have a HA setup, which now the only resource configured is Heartbeat with Active/Passive Configuration. Both running Debian 7, 64-bit in the cloud. Now i want to trigger an URL with the information ...
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1answer
285 views

IPTABLES for multiple Public IP Addresses

Currently i have two servers Running Debian 7 with HA Active/Passive setup using Pacemaker and Corosync as follows: node1->IP->xx.xx.xx.1 node2->IP->xx.xx.xx.2 VIP(Floating IP) ->xx.xx....
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1answer
301 views

How to integrate the fence_cisco_ucs.py(python) script with the pacemaker-1.1.10 and corosync-2.3.3

I have CentOS 7 on the Oracle VM VirtualBox. I have installed the pacemaker-1.1.10, corosync-2.3.3 and pcs tools. I able to create normalocf::heartbeat:IPaddr2 and ocf::heartbeat:apache etc resources. ...