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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Getting the DB2 Resource online in Failover Cluster

I'm using DB2 10.1 Enterprise Server Edition on Windows Server 2012 R2 After adding the DB2 resource to the cluster using the db2wolfi command, I go to the resources tab which is in the cluster ...
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1answer
1k views

Any problems with having an active/active HAProxy setup with Keepalived

Apologies if this has been asked before, but I can't seem to find much on it. We're going to be using HAProxy to load balance our MariaDB Galera Cluster. All the articles/tutorials I have seen on ...
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1answer
213 views

Regarding High Availability for MSSQL Server

Already used in MySQL : Real Time Replication (synchronization) between primary and secondary server is done using master and slave commands. So What is the equivalent feature for MsSQL. Which ...
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2answers
124 views

how to recover from a failed web server or reverse proxy

I have the following setup in my datacenter. Global LB --> HA proxy (2 instances on different servers via VRRP, performs HTTPS termination, acts as reverse proxy) ---> Nginx(2 instances on different ...
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89 views

Error when enabling HA on Xen Server

We have 4 Xen servers - 6.2 build 70446c - one shared storage - accessible via NFS. We disabled HA in order to solve some issues with a live migration that was stuck. I put the master on that pool in ...
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178 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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2answers
105 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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1answer
187 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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1answer
409 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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2answers
381 views

SQL Server Failover Cluster on Azure (HA Strategy)

In the context of SQL Server 2012 Standard Edition, is it possible to make Azure Blob storage available to a SQL Failover cluster directly as a shared SCSI resource on a Windows Cluster? An Azure blob ...
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1answer
190 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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466 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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3answers
2k views

Is round-robin DNS a possible solution for high availability?

Let's say I have 2 IPs for a given domain (round-robin DNS). If one the IPs becomes unresponsive, will clients try to connect to the other IP? or they will just fail to establish comunication with the ...
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1answer
2k views

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
82 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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2answers
804 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
125 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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93 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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82 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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1answer
187 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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5answers
1k views

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
234 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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83 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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1answer
145 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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339 views

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
176 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
78 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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3answers
73 views

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
337 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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1answer
114 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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1answer
112 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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2answers
844 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
155 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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2answers
42 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
123 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
78 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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1answer
317 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
255 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
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
54 views

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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436 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 ...
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2answers
566 views

How to change the master in a MongoDB cluster without restarting the process?

Reading the documentation of MongoDB about how to configure a master-slave configuration of a cluster (our cluster will have more than 12 nodes, so unfortunately we can't have a replica-set ...
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1answer
423 views

How to achieve high availability PostgreSQL on windows server 2008?

I am looking for a way to get a postgresql database running with high availability on some windows 2008 server boxes. I am not an expert in windows server administration nor postgresql, so I am a bit ...
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1answer
129 views

Setting up apache + mysql + exim on new servers. Redundancy/HA/Failover?

We are currently moving our single Linux server to a few other physical Linux servers, and would like to take the opportunity to have some more failover options. Backups are fine, and we don't ...
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2answers
108 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
382 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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2answers
2k views

Getting started with KVM coming from Vmware

In order to test new ideas and reduce cost I would like to test KVM. I think Vmware has these 3 things which are valuable: - HA which restart VMs (Virtual Machines) in other hosts when a Hardware ...
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1answer
117 views

multi-site web farm for IIS [duplicate]

I am having a terrible time finding information on this and I am hoping someone here can help or point me in the right direction. I am working on a project of setting up an IIS webfarm that is ...
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178 views

High-availability for ZMQ traffic

We have a lot of incoming third-party ZMQ traffic (zmq.PULL on our side). We need to implement a high-availability solution for that traffic. At the very least, we need to be able to manually switch ...
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1answer
362 views

How to make active/passive jboss resource in pacemaker

I want to configure my pacemaker for jboss server. I have 2 nodes with mysql master/slave configured. The problem is I want to start jboss on node which is located master database. The one possible ...