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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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 ...
3
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1answer
372 views

corosync binding to 127.0.0.1 instead of correct interface

I have the following problem when trying to implement a two-node failover cluster, using Hetzner as the hosting provider. my corosync.conf is as follows: # Please read the corosync.conf.5 manual ...
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1answer
266 views

corosync and multiple load balancers

I am trying to provide HA capabilities for our load balancers (nginx, pgpool and haproxy optionally) using pacemaker/corosync. I have defined three primitives: 1 for the failover IP, 1 for ...
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1answer
1k views

job interview - technical questions (hardware / network) [closed]

i recently had a phone interview, and did not get the job. i'm curious if i didn't get the technical questions correct, or whether there was something else about my interview that caused me to not get ...
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1answer
43 views

domain redirecting/forwarding during server shutdown temporary [closed]

I rack my brain how could I solve the following issue: my website/server needs to be available all the time, so just few minutes downtime could be critical I would run a separate server (server ...
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2answers
64 views

How to create a redundent webserver using virtual machines

I would like to create a fail-over web server using one physical box and 2 virtual instances. What I am aiming for is the host OS monitors performance of a web server running in a virtual machine (ie ...
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1answer
213 views

Is possible to use Pacemaker failover without hardware?

Is possible to use Pacemaker failover without hardware? On quickstart http://clusterlabs.org/quickstart-redhat.html you can find the followowing commands: ccs -f /etc/cluster/cluster.conf ...
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2answers
13k views

How to setup STONITH in a 2-node active/passive linux HA pacemaker cluster?

I am trying to setup an active/passive (2 nodes) Linux-HA cluster with corosync and pacemaker to hold a PostgreSQL-Database up and running. It works via DRBD and a service-ip. If node1 fails, node2 ...
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1answer
404 views

Log into a specific server in a Windows 2012 Remote Desktop Collection

I have 4 Windows 2012 Remote Desktop servers in 1 collection. All 4 of the servers have the RD Session Host role. I've also put the collection into High Availability Mode, so all 4 servers also have ...
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0answers
38 views

Prevent NGINX from rerouting to a backend that was previously down

I'm using NGINX's ip_hash directive to ensure that client requests always end up at the same backend server. In the case of a backend server outage, NGINX will reroute to the available server, and ...
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3answers
2k views

What happens if an OpenStack cloud controller dies?

I've been reading up on OpenStack and how we can re-create an EC2/S3-style cloud for our internal development and I'm having a hard time finding information on how the OpenStack cloud controller ...
3
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2answers
67 views

Is it possible to have automatic failover of a windows service without windows clustering?

Due to a partial failure of our SAN we have switched our message queuing (Active MQ) from using network storage to using local storage. Because the secondary server is no longer sharing the same ...
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2answers
710 views

Best way to load balancing between AWS and Rackspace?

I have a SaaS product hosted on AWS and I would like to have the same infrastructure hosted on Rackspace (or any other host) to offer a high availability (eventually load balancing) for my users in ...
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1answer
76 views

Windows Server 2012 Virtualization for Limited Downtime? [closed]

We're planning on purchasing a new server and consolidating most of our websites onto it. The initial thought was to use Windows Server 2012 with 4 VMs on it (1 e-commerce web, 1 e-commerce database, ...
2
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1answer
1k views

ESXi Beacon Probing Limitation - Three Switches Required?

We are currently using Link Status Only for our NIC Teams on our VM hosts, but recently ran into an issue where one of our two switches had a memory error and stopped passing traffic. All of our VM ...
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2answers
2k views

Per-packet round-robin load balancing for UDP

I need to load-balance UDP traffic between a number of "realservers" and do it in a truly round-robin fashion. I've started with keepalived, but unexpectedly discovered, that LVS treats UDP traffic as ...
8
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2answers
5k views

Can not switch drbd to secondary

I'm running drbd83 with ocfs2 in centos 5 and planning to use packemaker with them. Afer some time, I'm facing drbd split brain problem. version: 8.3.13 (api:88/proto:86-96) GIT-hash: ...
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1answer
193 views

Azure extra small vm availability set [closed]

My current extra small vm reaches the limits, so I decided to create a second extra small instance and add the two into a availability set so my service is everytime available and through the load ...
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3answers
451 views

How can I create a “fail whale” for my website?

I have a website that we load-balance across a few machines. The load-balancer (a Brocade ServerIron ADX) is on the local network. I know it has the capability to configure a "backup" ip address to ...
8
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4answers
6k views

What exactly does Gluster do?

I've been playing with gluster for the last 2 days and been asking questions here and on their questions system. I really don't understand some of the stuff. I see people saying stuff like Set up ...
0
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0answers
56 views

DRBD mount randomly unmounts itself

We have setup setup an NFS HA "cluster" using drbd/heartbeat. Everything works as expected when tested... If the instance nfs1 goes down, nfs2 picks up and everything seems to be fine. On both ...
1
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1answer
211 views

Bond0 Failover when link light stays up: High Availability Network

Configuration: Two switches, each with a separate internet route Centos servers with eth0 and eth1 bonded as an active-backup on bond0, eth0 in on switch and eth1 in the other /etc/modprobe.conf ...
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0answers
193 views

configure heartbeat HA on Amazon VPC instance

I'm trying to implement HA with Heartbeat (and monit) on two Amazon VPC instances. I read many articles about it and I tried all possible options I can think of. few articles I read (don't work for ...
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1answer
208 views

Memcached distribution

I have a question about memcached distribution across nodes. We have 20 memcached nodes with 200GB memcached on each. Our apps are PHP apps. $memcache->setOption(Memcached::OPT_DISTRIBUTION, ...
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3answers
822 views

Resilient Linux Mail Server Setup

How would people design a resilient mail server setup with Linux? On an application level what the system needs to provide is both an incoming and outgoing mail service (i.e. SMTP & IMAP), along ...
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0answers
1k views

LVM DRBD Shared between nodes proxmox

Context : I have proxmox cluster with the volume group shared with drbd for the VM - KVM. I have a problem with drbd. Indeed, when a node disconnect, the associate link between the differents nodes ...
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0answers
312 views

Strange Keepalived VRRP email notification

I have a 3 nodes keepalived (K1 to K3) installed and receiving email notification. The setup of keepalived is K1 VI_50, priority 100 VI_51, priority 98 VI_52, priority 99 K2 VI_50, priority 99 ...
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1answer
121 views

IP-based load balancing on external and internal interface

I have a certain distributed (as in, multiple components on multiple machines) service, that should be made available from the outside world. So, in LVS terminology, the clients are "on the internet", ...
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1answer
315 views

How to improve availability on a starting up PHP+MySQL application?

Yesterday, Rackspace DFW data center went down for a few hours and made me think on taking the delayed action of improving my server structure there. So far, I've been using a single CentOS instance ...
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2answers
681 views

Cisco Switch connected to 2 routers

I have following setup: The router on the left is a router on a stick to route traffic within the LAN that has different VLANS. The left switch is the root switch for our LAN and works as the VTP ...
2
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0answers
109 views

Solr on a two node Jboss cluster

Are there any issues with deploying Solr on two node jboss cluster with the index shared on a NFS mount point? We would like to do this for high-availability across data centers.
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4answers
4k views

Ganeti vs Proxmox [closed]

I'm system administrator in small software house. I'm going to virtualise our servers. The main reason for doing this is providing highest possible uptime, but probably it will also increase resources ...
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1answer
453 views

Clustering on cloud/VPS providers

I'm wondering if anyone can give some clustering recommendations to me. I'm currently on Linode, which I'm impressed and happy with, but they (along with just about every other VPS provider I know of) ...
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8answers
5k views

High Availability DNS Hosting Strategy?

I'm trying to find a few options of ways to do high availability DNS hosting for a few existing websites. This morning, the company I work for was brought to its knees because the DNS hosting we have ...
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1answer
233 views

SSL Session Persistence - HA Heartbeat

I have two servers, let's call them Milo and Otis. Now Milo and Otis are setup to be an active-passive pair of highly available servers where Milo is usually the master and Otis stands-by waiting for ...
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1answer
725 views

Howto setup 3-node heartbeat cluster?

I want to set up a virtual IP on three nodes using heartbeat. Currently, I have this: ha.cf: # Facility to use for syslog()/logger (alternative to log/debugfile) logfacility local0 # ...
2
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1answer
1k views

heartbeat: Bad nodename in /etc/ha.d//haresources [node1]

I'm trying to start heartbeat on Ubuntu 10.04 with service heartbeat start, but getting the following errors: heartbeat[24829]: 2011/11/22_19:31:07 ERROR: Bad nodename in /etc/ha.d//haresources ...
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1answer
536 views

could heartbeat v3 monitor service/resource status without pacemaker?

I am trying to setup a HA system based on CentOS, I want to use heartbeat v3 for the "heartbeat" mechanism, resource start/stop, looks heartbeat can get it done. But about the resource status, ...
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1answer
88 views

How to connect to mysql-master-ha from my application server

I am trying to use mysql-master-ha. I managed to get it connected with the master and slave mysql servers. Now I would like to know how to connect to mysql-master-ha from my web application server ...
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13answers
7k views

Move SQL-Server Database with zero downtime

Is it possible to move a sql server 2005 db to a different server running sql server 2008 without any downtime? The system is 24/7 and has to be moved to a different server with different storage. We ...
0
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1answer
642 views

Tomcat Failover High Availability (active / passive)

we have a jee web application running on apache tomcat , we need to deploy this application on production environment and we decided to use failover structure so we have one server active and another ...
0
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1answer
783 views

after split brain recovery filesystem not mounted

I have an active/passive high availability cluster with pacemaker+split brain. After split brain condition I use automatic split-brain recovery to recover my systems. The problem is that since file ...
0
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1answer
546 views

Setup HA postgres database, failover concept

I want to setup a HA postgres database. I setup master and slave database with synchronous streaming replication on different physical servers. When there is an error in the replication, the slave db ...
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1answer
3k views

How to setup a simple Ubuntu Server Tomcat cluster on VirtualBox for testing? [closed]

I am looking for the step by step instructions to setup at least two simple Ubuntu Virtual Core 12.10 Server VMs on Oracle VirtualBox under Windows 7 64bit. The test setup would be: Apache HTTP ...
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votes
5answers
2k views

When my A web server gets unplugged, how do I automatically redirect all the users to my B web server in another city, and vice versa?

When my A web server gets unplugged, how do I automatically redirect all the users to my B web server in another city, and vice versa? A load-balancing switch does what I want, except I can't figure ...
0
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1answer
284 views

MySQL High Availability with VMWare/DRBD/Heartbeat still common practice?

Is it still common practice to use a DRBD/Heartbeat solution for a high available MySQL Instance when the whole environment is virtualized (in our Case VMWare) Are there other/better solutions out ...
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2answers
482 views

Clustered file systems as XenServer storage

I want to use shared storage for a XenServer environment with 4 host servers which are running various VMs under XenServer. Planning to use 2 extra servers as storage with high availability of some ...
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1answer
901 views

Load balancing with High Availability - SQL Server + IIS using AWS

This is my first time load-balancing with high-availability using Windows and SQL Server. Looking for some validation and input on my planned setup. Now, typically when I want to create a HA ...
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0answers
73 views

Solaris and Hot-Standby

i have a short question. is it possible to create a hot-standby-cluster with 2 nodes and solaris 10? in Linux i would use DRBD and Hearbeat/corosync, but in Solaris? maybe do you have an tutorial? ...
3
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1answer
296 views

Virtual IP Failover when machine is overloaded

We have been using keepalived in combination with a virtual IP address for two years now. In the rare case that a machine crashes this works very well. But when there are issues on the box itself we ...