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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MSTDC in SQL Server 2012 - Windows Server 2012 R2 with high availability

We had implemented SQL Server High Availability on two physical servers over the VPN network. SQL Server 2012, Windows Server 2012 R2. It was noted that, Distributed Transaction was working perfectly ...
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39 views

Parallel filesystem which schedules simultaneous file requests to mutually exclusive sets of OSSs

My environment is RHEL based, interconnect is infiniband. I have some experience with Lustre. What i want to know is: Is there a parallel file-system, where if simultaneous write request arrive, ...
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5k views

multicast address use in corosync

I'm wondering about the purpose of the multicast address in the corosync messaging software : Since we have to bind each net interface with an IP address and a specific port, and each ring communicate ...
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405 views

Most efficient way to setup massive high-availability storage in Azure to work with multiple VMs?

I'm looking into various options for setting up massive high-availability storage in Windows Azure, to use together with my Azure VMs. The VMs need to be able to work with the storage as if were a ...
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2k views

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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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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4answers
1k 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
331 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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191 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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2k 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 HSRP....
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176 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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1k 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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221 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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3k 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
232 views

SOA architecture requires 99.9% availability -> 9hrs max downtime -> physical architecture mapping?

External architects have designed an architecture for a Service-Oriented Architecture environment. They fixed the availability to be 99.9%, equivalent to max 9 hrs downtime [per year]. Where can I ...
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519 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
273 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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130 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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316 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
187 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
2k 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
823 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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926 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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316 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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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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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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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
131 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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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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216 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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145 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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112 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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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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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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340 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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105 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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(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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755 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
342 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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130 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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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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630 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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128 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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165 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
2k 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
237 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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44 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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157 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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95 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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538 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 ...