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 Server Virtual Network Name Change Error

I am in the process of configuring a two-node failover cluster for a migration project. We are transitioning a stand-alone SQL Server to a cluster. Environment: 2x nodes with Windows Server 2012 R2 ...
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4answers
58 views

new hyper V High Avaliability setup and SMB 3.0 storage

I am looking at building an new 2012 R2 with Hyper V setup, everything has to be HP hardware. 2x HyperV 2012 R2 servers running 20-30 VMs. These will be dual 6 core xeons with 128gb of ram. 2x 2012 ...
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2answers
60 views

Firewall high availability

Context: My company is on the verge of a major network improvement, we will expand our network to remote offices via radio bridges. The firewall will be handling: 3 mission critical networks 3 non ...
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3answers
78 views

Options for high-availability of a smallish website? [closed]

I'm running a website that gets ~1500 visitors a day. It's not a ton, but I want to make sure this site stays up nevertheless. Currently, we're hosted on a shared hosting provider and the site has ...
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1answer
89 views

SonicWALL HA w/ Dual WAN HSRP from two redundant switches

We're adding two SonicWALL NSA 2600 firewalls to our current setup. We currently get two WAN connections from two separate Cisco routers running on the same external subnet with what I believe is ...
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1answer
80 views

NFS failover fails with stale file handles while migrating resources

Running into a bit of a problem here , I set up two servers ( Centos 6 ) with Glusterfs and a shared directory between them, I have moved the nfs directory to the shared Gluster folder and have ...
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2answers
732 views

Xen Remus setup

Currently, I'm running the IT for a small organization, and we just purchased a new server to replace our aging Dell poweredge. As the Dell isn't so bad as to be junk, I was hoping to set up Xen on ...
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1answer
26 views

VMware ESX 3.x: How to connect two ESX server to a single VMFS datastore on SAN

I'm generally a networking guy but I'm trying to learn VMware. I'm running two ESX 3.x servers with virtual center. I know that it is possible to create redundancy or high availability by configuring ...
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30 views

High availability MySQL with HA Proxy failover

I am looking to load balance a Percona cluster behind two HA Proxy nodes with failover (using keepalived) so there is no single point of failure. I have HA Proxy already setup with keepalived using a ...
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0answers
16 views

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
65 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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3answers
4k views

What is the difference between keepalive and heartbeat?

I want to structure a high available server cluster . Now I want to know detail about keepalive and heartbeat, what is the difference between both, and How to choice one.
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3answers
783 views

How to make cronjobs high available?

What would be a good solution to make a failover pair that has multiple cronjobs running avoid running the processes twice? Either in failover, or by dividing the jobs between them, and of course ...
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7answers
3k views

How to perform cron jobs failover?

Using two Debian servers, I need to setup a strong failover environment for cron jobs that can be only called on one server at a time. Moving a file in /etc/cron.d should do the trick, but is there ...
3
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1answer
42 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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0answers
16 views

“API” to halt server with HAProxy (by loadbalancer.org) [duplicate]

I have a HAProxy load balancer by loadbalancer.org. I have 3 servers in the cluster and have to halt a server once in a while, for example when I release new code on the server. I would like to be ...
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2answers
37 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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0answers
27 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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1answer
254 views

Should VMware HA Admission Control be enabled for small (2/3-host) clusters?

Take the following common scenario... A basic vSphere cluster running two or three hosts, shared storage and a token set of virtual machines under Essentials Plus or greater licensing. Should HA ...
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4answers
1k views

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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0answers
69 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
29 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
45 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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45 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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1answer
53 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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20 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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21 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
132 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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18 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
723 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
40 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
84 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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33 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
72 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
802 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
4k views

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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74 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
89 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
202 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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2answers
272 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 ...
6
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1answer
193 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 ...
3
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1answer
49 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
239 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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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
25 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
429 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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36 views

How do I choose a failover strategy for Mysql 5.5?

I have 2 mysql 5.5 database servers that I've just set up on Ubuntu 12.04. What I would like to do is provide a means of having these failover. Ideally using an HA strategy like keepalived so that ...
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15 views

Repair tables after pacemaker + drbd migration/failover

I have a master/slave pacemaker/drbd cluster that handles mysql, apache, and some other stuff. I'd like to have mysql automatically repair tables (mysqlcheck -A --auto-repair or similar) after ...
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1answer
96 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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245 views

High availability squid farm

I'm trying to configure a high availability squid farm on CentOs 6.4 with haproxy1.5 for load balancing and ucarp1.5.2 for ip failover alongside squid3.1.10, running on each server these are my ...