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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Icinga2 dependecies of devices on HA

I would like to configure a Host-to-Host dependency on Icinga2, however, one of the Hosts has an HA configuration, so I need the to trigger it only when both HA devices are down. Suppose this ...
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1answer
14 views

Distributed mirrored filesystem under FreeBSD

Can someone share their experience in building a distributed mirrored filesystem between multiple FreeBSD machines? I. e. we have two (three, four...) servers and special partition "part1" mounted on ...
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1answer
137 views

Can my redundant network setup be made more robust?

With my current design I have a DL380 Gen9 running ESXi. It has redundant NICs cabled to two different switches. Those switches in turn are both cabled to a third switch that allows my workstation to ...
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1answer
34 views

Setting up a virtual IP for high availablity [closed]

Disclaimer; I'm completely new to server maintenance, availablity and clustering. I'm trying to achieve a high availablity server cluster configuration (failover, no load-balancing). I have two ...
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1answer
20 views

Change Xenserver 6.5 Pool Master

I'm looking to change the pool master because my current pool master is having some hardware issues. I've disabled HA and I came across this script to change the pool master to my other server: xe ...
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23 views

Is rsync reliable for syncing uploaded files of a LAMP-Application on 2 servers?

We are currently designing the architecture for a High Availability setup of our LAMP application. The last critical question is, how to access the user uploaded images on server 1 from server 2 and ...
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3answers
40 views

How to design high availability system [on hold]

Suppose I have some web applications & also some desktop applications running on a server in production environment. In production environment, even a single minute downtime is not tolerated. ...
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18 views

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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1answer
21 views

Keepalived failover not working - how to configure master / failover

I have following two server setup running: node1: keepadlived master -> HAProxy -> Apache node2: keepadlived failover -> HAProxy -> Apache The system works perfectly until I shut down keepalived ...
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1answer
15 views

How to configure keepalived - not able to setup VIP

I am trying to setup a comiled keepalived 1.2.19 on ubuntu 14.04 with failover. Somehow the virtual ip never shows up: ip addr show eth0 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 ...
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1answer
25 views

Failover dedicated servers using DFS or use Cloud hosting

Currently I'm running a number of ASP.NET applications on a single dedicated Windows 2012 Standard R2 server with a hardware firewall in front. If this server goes down, my applications cannot be ...
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1answer
35 views

Configure HA Proxy with two application servers to handle fail-over

I have configured two application servers with HA Proxy to recover from fail-over situation. So I want to configure HA in such a way that if my 1st application server goes down, then only next ...
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1answer
58 views

SAN storage I/O issues [closed]

I have a relatively busy application running on a dedicated server. The spec is 8-core Xeon(R) CPU E3-1240 v3 @ 3.40Ghz 16GB RAM 8TB RAID 10 80GB SSD for MySQL I use Wowza Streaming Server to ...
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53 views

DNS round-robin requests not distributed evenly

We have setup two DNS A records, where each points to a load balancer. nslookup ourdomain.com Server: 8.8.8.8 Address: 8.8.8.8#53 Non-authoritative answer: Name: ourdomain.com Address: ...
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0answers
19 views

Multi Path VRRP with keepalived

I'm migrating from an old heartbeat setup to using keepalived at the moment and currently I can't find how to replicate the heartbeat capability of using multiple links as cluster interconnects in ...
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0answers
29 views

can AWS load balancer auto restart out of service images?

I have set up a load balancer with two instances in two availability zone I set up an health check to ping a specific page of my webapp now I'm trying to find if the load balancer health check could ...
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0answers
38 views

Considerations for SQL Server 2012 when performing in-place OS upgrade to 2012 R2

I'm running SQL Server 2012 Enterprise (11.0.3381.0) on Server 2012 (6.2.9200) and am preparing for an in-place OS upgrade to 2012 R2. We've got an Always-On Availability Group in a 2-server cluster ...
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1answer
31 views

Gluster FS. Rebuild replicated volume

I am playing with GlusterFS. And now I am curious how to fully rebuild replicated volume. So I`ve created 1 replicated volume from server1 and server2 nodes: root@server1:~# gluster volume create ...
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2answers
116 views

How to configure a web hosting server to be tolerant of ISP failures?

We need DNS fault-tolerance for our ISP We host a number of web sites on a local CloudLinux server running cPanel and WHM. The server itself is it's own DNS server. The server lives in our ...
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2answers
43 views

SQL 2012 Availability Group Doesn't Failover When Shutting Down Service

I am having an issue with SQL 2012 Availability Groups where it does not fail over when shutting down the service. When you shut down the service you will get an error: A network-related or ...
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1answer
21 views

SQL Server 2012 AlwaysOn Availability Groups Server Logins Fails When Switching Between Nodes

I am setting up a 3 node cluster as part of an availability group. Initially I tested failover between nodes using SQL Management Studio and everything failed over successfully when I stopped a node, ...
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92 views

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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33 views

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
74 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
73 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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143 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 ...
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1answer
116 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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23 views

mysql-ha in cloud failover

we have mysql linux 5.6 databases in AWS EC2 and we like to implement a multi region HA solution so we have no downtime and can fail over, what steps tool strategy you suggest?
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1answer
20 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
81 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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72 views

Heartbeat fails to start

I have two virtual machines running CentOS 6.6 (I use WMware workstation). I have heartbeat installed and configured on both. The configurations are: /etc/ha.d/ha.cf udpport 694 debugfile ...
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69 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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1answer
50 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
75 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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69 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
156 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
164 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
103 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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1answer
97 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 ...
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35 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
215 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
98 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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42 views

SQL Mirroring with Certificates and Domain?

We're replacing all our servers and wish to migrate a mirrored database running in one domain to the new servers in a different domain without downtime. Is it possible to turn off mirroring in the ...
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0answers
68 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 ...
2
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1answer
212 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
79 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 ...
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1answer
37 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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35 views

Ucarp on vlans in trunk - debian

is it possible to use ucarp on vlan interface in debian ? I am trying : auto eth1 iface eth1 inet static address 192.168.0.1 netmask 255.255.192.0 auto eth1.10 iface eth1.10 inet static ...
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2answers
75 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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53 views

RHEL KVM HA rgmanager

I have a RHEL HA 2 node cluster which is run with rgmanager, cman (corosync), clvmd, gfs2 and storage replication using drbd I let drbd, clvmd and gfs2 be managed by rgmanager, but i have 8 ...