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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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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149 views

XenServer HA with only internal storage

I am new to XenServer 6.2. I have 2 Dell machine, each with 24GB RAM, 3x600GB HDD. It is possible to run VM in XenServer on 1 machine and then replicate to another Dell machine as HA. I went through ...
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1answer
61 views

Make keepalived send 0 priority when going to FAULT state

When stopping (service keepalived stop), keepalived does send the priority 0 adverts so the backup server takes over almost immediately. However, when it goes to fault mode (check script returns not ...
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2answers
92 views

best way to load balance dual esxi

Im hosting a few websites on a single ESXi box that runs Windows Server 2008 R2 with IIS 7. Now I would like to make sure that if the host goes down, the websites will still be live, so I've ordered a ...
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159 views

Configuring VRRP with keepalived on two machines - interaction with proxy arp

Let's assume we have the following topology for our network: Host1------- Router1-------Router2----------Router3-------Host2 and we want to configure vrrp on the two hosts with keepalived so that ...
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130 views

How to implement virtual IPs on AWS?

Is it possible to create floating IPs within Amazon? More specifically within the VPC? If so, how can I do this? Their documentation doesn't seem to point me in the right direction. The best I could ...
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94 views

RabbitMQ: Every other message failing to deliver/enter into queue after high availability failover

I'm currently in the process of setting up a two node rabbitmq cluster, but i'm encountering some issues when it comes to high availability. I've got clustering set up correctly on the nodes: ...
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58 views

Drupal High-Availability solution

I am trying to create a HA environment with 2 Virtual servers (CentOS 6.5) running Drupal over CPanel. THe DNS part is already solved and the solutions I have seen in Google looks quite complex. I ...
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1answer
276 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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75 views

Running two different application servers on the same Oracle RAC database

I would like to set up a basic high availability solution for one application server (Tomcat, JBoss). Is it possible to run to clone each application server and connect clone a to node1 and clone b to ...
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1answer
2k views

Keepalived's virtual_router_id - should it be unique per node?

I have two nodes running keepalived, and two VIP, e.g. Node 1 Node 2 VIP1 VIP2 So in each node, I have two definition of vrrp_instance, so I assume the two vrrp_instance in my ...
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1answer
103 views

Monitor a ucarp VIP using another interface

On Debian machines, I would like to setup a VIP between two nodes for a public IP, but I would like to avoid using three IP addresses to make ucarp communicate between the two nodes. Can I set it up ...
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1answer
360 views

LAN Redundancy - NIC, Cables + Switch?

I'm trying to move to a HA solution and would like to understand what hardware is required to have redundancy in the NICs, switch and cables. The diagrams below show how I envisage a non-redundant ...
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1answer
168 views

ASA High Availability failover link configuration

According to the Cisco ASA 5500 Series Configuration Guide, Cisco's preferred method of configuring your network for ASA High Availability is as such: They have two switches on External, two ...
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2answers
957 views

High availability LDAPS with Fedora Directory Server

I've been asked to set up a HA LDAP architecture using Fedora Directory Server - the company currebnly uses Sun DS but wants to move away from Sun. I want to use a network hardware loadbalancer ...
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4answers
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SonicWall “gotchas”?

We're looking to move away from PFSense and CARP to a pair of SonicWall NSA 24001 configured in Active/Passive for High Availability. I've never dealt with SonicWall before, so is there anything I ...
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0answers
386 views

keepalived - random re-elections

We have set up 3 servers running keepalived . We started noticing some random re-elections occurring which we can't explain so I cam here looking for advice. Here is our configuration: MASTER: ...
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2answers
102 views

Why does DRBD infrastructure resyncs whole partition several times a day

I have a Primary/Secondary 2 nodes DRBD setting as shown global { usage-count no; } common { syncer { rate 4M; } } resource r0 { protocol B; startup { wfc-timeout 15; ...
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2answers
658 views

How to scale up a web server supporting long polling

I am planing to add more web application servers to support increasing clients, deploying HAproxy and Keepalived for load balancing and High availability. My server usage has the following ...
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1answer
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Why doesn't VMWare DRS automatically migrate VMs when a host is put in maintenance mode?

We have 4 ESXi 5.0 hosts in a VMWare cluster on shared storage (NFS) with DRS and HA on. We want to perform a memory upgrade on one of the hosts. We put that host in maintenance mode but DRS did not ...
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1answer
77 views

High Available SQL Server without SAN by using AlwaysOn feature

I have two Microsoft SQL Servers (v 2012) and I want to make them mirror and when one of them goes down the second one will be replaced. AlwaysOn is a new feature in SQL Server 2012 that is ...
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1answer
343 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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75 views

bgp and incomming requests

I have IP pool, 2 providers and BGP on RouterBoard. First provider is default. Second is backup. If first provider falls - outgoing connections works on second. But incoming still routed to broken ...
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0answers
68 views

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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5answers
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Windows Server 2012 Hyper-V Failover Cluster + Active/Active HA storage solution

I have a question. I need to build active/active HA storage architecture, but I don't know how achieve this without expensive third party software. I have two Hyper-V hosts, each with iSCSI storage. I ...
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1answer
171 views

Redundant web static content storage - what technologies? (small scale) [closed]

Current situation of our static web servers: 2x 2U servers full of SSDs (raid5) for storing data data are written to them only through our applications (*) huge amount of small image files (one ...
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1answer
118 views

Red-Hat Cluster doesnt migrate services on node shutdown

I have a RHCS with two nodes and manual fencing. when I restart Node 1 (the primary) it migrates both services to Node 2 automatically. but when I shutdown Node 1, it doesnt happen and I need to use ...
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1answer
187 views

How to implement High Availability easily?

I have a website that is currently hosted in a single DigitalOcean region. DO are great, but occasionally they have routing issues in a region and the website goes down. The stack is very simple - a ...
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0answers
73 views

HP Blade based georedundant configuration / IRF

I'm planning to deploy 2 georedundant server farms. We chose HP Blade system. Every site would consist of: 1 x C3000 enclosure 4 x BL460c servers equiped additionally with 554M mezzanine (to have 4 ...
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376 views

Memcached and repcached not replicating 2 master servers

I have memcached-1.2.8-repcached-2.2 installed on memcached on centos. They install went great and when i start memcached i get: replication: connect (peer=192.168.1.2:11212) replication: marugoto ...
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1answer
123 views

(simple) linux HA with vmware vsphere?

I hope my upcoming question is specific enough, and you are able and willing to support :-) We have several openSUSE VMs in an ESX-Cluster (three ESX-Servers) with an attached iSCSI-SAN. All of ...
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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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1answer
109 views

High availability NFS

We're considering hosting a web application on Amazon AWS. I've drawn a proposed setup for it, which I will try to summarize in a few lines: The web application is served from webservers in 3 ...
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1answer
150 views

Fault-tolerant network access to redundant storage in a heterogeneous environment (including Windows)?

We are facing a design "challenge" where we are required to set up a storage solution with the following properties: What we need HA a scalable storage backend offline/disconnected operation on ...
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1answer
101 views

Remus or alternatives

Is it possible to set up Remus to act as a high availability server across 3 locations. Has anyone set up something like that. That is A would be main site, which would have an HA set up at B, and C ...
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3answers
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If my DNS is a VM with HA do I need a secondary?

Same question would apply to mail server - if I have these running as VMs with failover / HA do I need to run a secondary / backup for either? This is a relatively small site (< 50 machines) so ...
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1answer
113 views

Best PostgreSQL HA strategy for 99% read scenario?

I'm in the process of building out a new PostgreSQL (9.3) environment in which traffic hovers around 99% read. We'll have 2 very powerful machines, connected via 1Gb ethernet. With the multitude of ...
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2answers
712 views

Is it possible to balance load between multiple Nginx load balancers without using a hardware load balancer?

I plan to balance load between my app servers using a separate Nginx server as a software load balancer. But actually, it's because a load balancer in front of the app servers allows me to update an ...
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2answers
136 views

Any software/proxy that can do SMTP failover?

I'm using a monitoring software that sends out email to my ISP's mail server (SMTP Server). But sometimes, the ISP's mail server goes down, or takes too long to respond, I would like to find out if ...
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1answer
509 views

GlusterFS as elastic file storage?

Is there any way to run GlusterFS in a replicated mode, but with the ability to dynamically scale the volume up and down? Say you have 3 servers all running glusterd. your Gluster volume would have ...
10
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1answer
1k views

Replicating beanstalkd for High Availability

Title says it all. Does anyone know of a way to replicate beanstalkd such that if a beanstalk server went down, others slaves could take over? Here's one approach I thought of: I could make ...
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2answers
40 views

DNS failover in virtual network

I have read some articles here and on other websites about the drawbacks of using DNS to implement high availability services. This is mostly due to the fact that configuring DNS to work efficiently ...
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1answer
287 views

Solr Replication without using zookeeper

The application that I am currently working on does not need real time indexing. I am using Solr as the indexing engine and I want to setup a High Availability Solr cluster with 2 replica nodes. Seems ...
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6answers
245 views

Use two website hostings for better availability

I have two VPS servers from two different hosting companies. I want to make some fallback to second VPS if first is not available (preferably automatic). I understand that if I have a single ...
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1answer
74 views

How to install pulse during RHEL 5.9 install

I am desperately trying to install pulse on a rhel5.9 machine. I have tried googling all over but all I get are instruction on how to configure pulse/piranha on an already installed box. I have ...
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2answers
2k views

Keepalived over GRE tunnel for failover on VPS environment

I'm running an application on Linode. Their network does not support multicasting. Many tools used for failover (keepalived, spread/wackamole, hearbeat) require multicast to work (as far as I know). ...
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339 views

Using DRBD with 100mbit uplink

we are planing to use drbd to sync two servers (different hardware) to get kind of HA in case the master server dies. The servers are hosted physically in the same datacenter (Hetzner in germany) and ...
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1answer
65 views

Off-site HA server

I understand that this is a little too broad question, but I hope I can get some guidelines here. I have a CentOS 5 server with cPanel on it. It is extremely important not to have downtime, but ...
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2answers
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What software should I use for fault tolerence/high availability for 2 servers [closed]

What are some of the industry standard enterprise software to allow fail-over or swap-over between 2 servers? E.g., if 1 server goes down(due to connection or power, etc), the other kicks in either ...
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382 views

How to configure cluster.conf for failover routing two networks?

I'm routing between an "external" subnet with Internet connectivity and two "internal" subnets, using iptables forwarding on a Linux box running CentOS 6.4: I'd like to now duplicate this router ...