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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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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92 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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221 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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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 ...
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153 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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172 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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44 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
28 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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145 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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47 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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48 views

Multiple Subversion Servers behind a load balancer

I'd like to add a little redundancy to my subversion setup. I'd like to have multiple servers share a common NFS mount and load balance http requests to the servers (with stickiness). Is this an ...
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2answers
97 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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96 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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87 views

Heatbeat is not assigning a virtual ip

I am trying to setup HA Cluster with Heartbeat on CentOS here is my configurations. $ cat /etc/ha.d/authkeys auth 2 2 sha1 test-ha $ cat /etc/ha.d/ha.cf logfile /var/log/ha-log ...
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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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129 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
421 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
93 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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356 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
150 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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158 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
181 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
165 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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59 views

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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119 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
190 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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201 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) ...
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131 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. ...
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31 views

S3 dropouts in one region only - is this normal?

I'm using S3 to serve static image assets to a website. I'm a developer in Montréal, Quebec. My client's office is in LA. Once every month or three we're seeing S3 completely fail to serve images to ...
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1answer
110 views

vSphere High Availability, Fault Tolerance and Snapshots

I've heard claims from a vSphere server administrator that VMs configured for high availability continue to transparently function even in the event of an ESXi host failure. He also claims VMs ...
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204 views

Server 2012R2 DFS High Availability - with local storage?

Can I use clustering for high availability on two identical 2012R2 boxes that use LOCAL storage (not attached or SAN)? Local storage is super cheap and scalable, which is why the SAN has been ...
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265 views

the pacemaker can't start the drbd resource

here is crm the configure show [root@node1 /]# crm configure show node node1 node node1.mycluster.org node node2 node node2.mycluster.org primitive Apache apache \ params ...
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1k views

pacemaker config resource for nginx

i'm trying to build cluster by two vm using virtualbox i follow this tutorial http://www.tokiwinter.com/clustering-with-drbd-corosync-and-pacemaker/ and type the command as below [root@node1 data]# ...
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219 views

MariaDB Multimaster replication and AWS Auto Scaling Group

One of the things I hate most about RDBMS is that it can't sit on an ASG like the web servers and bounce it around and scale it up and down like a yoyo. Or can it? Recently looking at MariaDB galera ...
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110 views

Add security/authentication to mongodb (2.6) without downtime?

We have a 3 node replica set (running 2.6.1) that's running mostly defaults. We'd like to add authentication, but do it without downtime. I'm fine with restarting the nodes one-by-one and even ...
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142 views

Corosync 2.3.3: Unable to enable cipher

I'm trying to set up a new pacemaker/corosync stack of 2 machines. I was using it before with corosync1, but on Ubuntu 14.04 I've got corosync 2.3.3 OK - I said, and tried to use this version of ...
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Never miss a HTTP post [closed]

I have a webservice that have a couple of "machine" clients connected to it that does HTTP post with data once in a while. The nature of the service is that I cant allow the service to loose a single ...
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59 views

Running iSCSI LIO with high availability

I've build a two node storage setup with OCFS on top of DRBD to provide storage for a couple of ESXi servers. Will it be possible to setup iSCSI targets on both storage nodes and make one of the nodes ...
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562 views

Centos 6.5 configuring HA cluster

I need to configure HA cluster using 2 computers. But I've got a problem, when I'm trying to start a heartbeat service it starts but throws an error. Here's the error message: Starting ...
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1answer
127 views

High Availability/Failover hardware hookup

I'm learning about clustering and high availability techniques, and stumbled upon an article about configuring a network with a pair of servers, using DRBD for replication and heartbeat for monitoring ...
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2answers
719 views

corosync fails to install

I was trying to setup cluster using corosync and pacemaker on RHEL6 (CentOS release 6.5) I have added following repo data [haclustering] name=HA Clustering type=rpm-md ...
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1answer
125 views

Why to use fencing when you already have redundant communication links?

This article stays that you should use both fencing (aka STONITH) and redundant communication links. I'm trying to understand what benefits STONITH gives in case of split-brain. Consider for example ...
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2answers
848 views

Which STONITH hardware for power fencing?

I'd like to setup a two node high availability cluster using corosync/pacemaker/drbd. For that, of course, I need fencing. As far as I understand, all IPMI/iLO/... solutions do the job, but only as ...
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2answers
1k views

Static IP in AWS but with possible Load Balance feature

I am playing a bit with AWS. My goal is to setup infrastructure, which will have static IP on outgoing connections (requirement from payment provider which solution has been implemented in our app) ...
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1answer
548 views

Simple fencing/STONITH script in Centos 7

I am installing a simple Corosync/pacemaker/drbd high availability cluster using Centos 7 and would like to provide fencing/STONITH using custom hardware (power switches using USB connections). As ...
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HA router with keepalived showing unexpected traceroute

I have a couple of routers in HA using keepalived vrrp daemon under linux. Here are the addresses x.x.x.129 floating (keepalive) x.x.x.130 router1 (static) x.x.x.131 router2 (static) Something ...
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88 views

Load balancing for a running server process with sessions

I'm developing a server application that accepts incoming connections and works with client applications. The customer wants to have two machines working: in case one goes offline, the second will ...
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3answers
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Web-based System High Availability [closed]

I'm a SysAdmin in one of the construction sites in a remote place. There is no reasonable internet speed can be reached there except a poor 3G/4G signal coverage which provide the users with ...
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1answer
918 views

redhat cluster failover not working (corosync [TOTEM ] Retransmit List)

I'm using following: [root@kpdbm01 ~]# cat /etc/redhat-release Red Hat Enterprise Linux Server release 6.5 (Santiago) [root@kpdbm01 ~]# uname -a Linux kpdbm01 2.6.32-431.20.3.el6.x86_64 #1 SMP Fri ...
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1answer
92 views

Avoiding a Single Point of Failure with link aggregation

I have a requirement for a system with no Single Point of Failure. The client have offered two Ethernet cables per server. Each of the servers will connect into their network, however I want to ...