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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Dell switches, LAG config, ports stay lit when device powered off

I have two Dell switches configured in a stack (with stacking cables). I have four ports on each unit in the stack configured in two separate LAGs as follows: Unit 1/P1: LAG1 Unit 1/P2: LAG1 Unit 1/...
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1answer
79 views

What is the best practice for deploying dev database to live system?

My developers in a project want to have the dev db on dev server synced with live db on live servers, which I think is a bad idea. Despite that, what is the best way to deploy a codebase+db to live? ...
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1answer
282 views

How to set up an automatic failover reverse proxy for two identical Icecast master servers?

I'm trying to do simple everything double with a reverse proxy in the front high availability for an Icecast master streaming server (i.e. I'm not talking about Icecast relays here). So, three VMs: ...
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1answer
35 views

how to prevent Innob db spiking at 97% Disk I/O Utilization

Our database(InnobDb) is spiking at 99% I/O at random times. After the spike it goes down to about 2% until it spikes agian. There are not some "super" queries that are running in these intervals. We ...
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2answers
114 views

server crashes under high load

We are running a setup that has gotten a lot of media attention these days and we expect the traffic to continue. We have 1 haproxy loadbalancer, 3 application servers(2 image, 1 general) and one ...
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1answer
70 views

2 Node Failover Cluster

I need to build a 2 node Hyper-V failover cluster, that's dead simple right? The problem is that the hardware is already bought. Both servers are identical and approved. Related spec: 250GB Drive ...
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1answer
74 views

IP configuration of cluster application to database server

I need to setup the IP of a cluster of applications servers to connect to a cluster of database servers. For 1 to 1, application server to database server is quite easy, but when comes to a cluster ...
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0answers
143 views

HAProxy failing at random times (backend has no server available!)

I have a CentOS 7.1 (x64) droplet configured to load balance between 2 apache/php servers. I have it working perfectly, but randomly throughout the day it reports the following: haproxy[12947]: ...
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30 views

Minimal Rails server OS for use with High Availability (XenServer)

I have multiple XenServers configured with High Availability. I have multiple simple Rails apps that talk to each other and form a higher purpose. I have a postgresql database. Is there any distro ...
0
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1answer
66 views

Use Azure availability set or deploy to single instances to paired region for HA

Considering that Azure will not roll out an update on paired regions simultaneously during a planned maintenance of virtual machines with single-instance configurations, is it a good strategy to have ...
0
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1answer
51 views

Looking for Failover Cluster for Scientific Linux and nginx [closed]

here is what I'm trying: two instances of SL7.1 with nginx as reverseproxy no shared filesystem shared resources: virtual IP running nginx service I already tried keepalived and corosync + ...
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0answers
168 views

pgpool: ip addresses conflict after master failed

I have two servers with pgpool in master-slave architecture. Virtual IP | | ------------- ------------- ...
4
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1answer
229 views

Can Azure availability set span 2 regions (Dublin, Amsterdam)

Is it possible for 2 VMs to be provisioned in 2 different regions (West & North Europe) and still keep them in the same availability set? Is region the correct word to refer to the datacenter(s) ...
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1answer
147 views

Xenserver 6.5 High Availability

I'm running xenserver 6.5 and I just configured high availability. I noticed that there is the option for start order. Is there a best practice for start order when it comes to HA? Obviously the more ...
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0answers
205 views

nginx high-availability with corosync and pacemaker

I configured nginx in a failover with corosync and pacemaker. Everything looked until the test of the failover: The VirtualIP is transmitted to the other host, but the resouce reverseproxy fails to ...
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3answers
238 views

AWS Elastic Container Service - Run service in multiple availability zones

I am running long running tasks via ECS. The container instances are spread over multiple availability zones. Is it possible to define in ECS that when having more then 1 instance of a task, each task ...
0
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1answer
28 views

Negotitate VRRP on a private link between routers (Possible?)

I have a topology similar to this one: R1 and R2 are two physical machines acting as routers. (Running some linux distro with Keepalived) R1 and R2 are connected to one another with a private link. ...
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1answer
49 views

RHEL HA cluster, is it possible to get a notification upon failover

I have configured Linux HA cluster on RHEL 7.1, can i get a notification upon failover or is it possible to start the crashed resource automatically ?
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1answer
348 views

High availability and AWS VPN

I have a question about achieving high availability over an AWS VPN. Context: I have a requirement to establish a site to site VPN connection between my AWS VPC and a big corporate. This VPN link is ...
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0answers
479 views

How to configure Failover IPs for High Availability with Hetzner Online

I have a cluster of 3 Ubuntu nodes running in VMs in the lab and want to take it now to production. Hetzner Online hetzner.de offers some good value dedicated servers, so I rented 3 machines, ...
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2answers
272 views

What is the best way to sync 2 identical centos servers in real time

I am operating a centos linux server(A) and I want to create a realtime backup server(B) so whenever server A goes down server B(after the failover kicks in) will take over. I already solved the ...
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1answer
310 views

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 scenario:...
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1answer
294 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 ...
3
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1answer
203 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
1k 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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3answers
76 views

How to design high availability system [closed]

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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0answers
159 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
249 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
119 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
97 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 used,...
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1answer
72 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 ...
0
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1answer
108 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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106 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: 52....
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88 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
84 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
78 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
86 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
191 views

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

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 building,...
0
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2answers
157 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 instance-...
0
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1answer
135 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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0answers
439 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. ...
0
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0answers
138 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
138 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
545 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 ...
3
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0answers
601 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 help....
2
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1answer
447 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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1answer
27 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 ...
2
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1answer
2k 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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0answers
179 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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2answers
261 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) ...