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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Microsoft SQL Server Standard High Availability without Shared Storage

I'm a software dev with little experience managing SQL so please bear with me! We are developing a piece of software that needs to be highly available, with a significant degree of resilience. This ...
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redhat cluster failover not working (corosync [TOTEM ] Retransmit List)

I'm using following: [root@kpdbm01 ~]# cat /etc/redhat-release Red Hat Enterprise Linux Server release 6.5 (Santiago) [root@kpdbm01 ~]# uname -a Linux kpdbm01 2.6.32-431.20.3.el6.x86_64 #1 SMP Fri ...
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162 views

Avoiding a Single Point of Failure with link aggregation

I have a requirement for a system with no Single Point of Failure. The client have offered two Ethernet cables per server. Each of the servers will connect into their network, however I want to ...
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iptable CLUSTERIP doesn't work

We have some requirements which explained here. We tried to satisfy them without any success as described. Here is the brief information: Here are requirements: High Availability Load Balancing ...
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Multimaster Keepalived Configuration (Virtual IP with Load Balancing)

Here are requirements: 1. High Availability 2. Load Balancing First configuration 1. Two linux servers have been configured with one static IP for each: 10.17.243.11, 10.17.243.12 2. Keepalived has ...
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465 views

HA - Heartbeat / Pacemaker - CentOS - Manual Symlinks

I have a MySQL Master <> Master pair setup for HA. I would like to setup automatic failover not just if the node hosting the current write mysql instance goes down, but also if the mysql instance ...
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2answers
587 views

Keepalived loses VIP upon power cycle of master

I have two servers running Keepalived 1.2.7 with hostnames left and right. Here are the configs: # keepalived.conf on left vrrp_instance VI_1 { state MASTER interface eth1 ...
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1answer
385 views

uwsgi + Django with nginx: High Availability Setup

Moved from : http://stackoverflow.com/questions/25304968/uwsgi-django-with-nginx-high-availability-setup to here. I was setting up High Availability on RHEL 6.5 . My Stack is 1. uwsgi 2. nginx ...
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How to lower Gluster FS down peer timeout / reduce down peer impact?

The setting: Two fresh CentOS 6.5 server with latest updates. Both have a fresh install of Gluster 3.5.2. What I did ( from the perspective of server 2, shared1 and shared2 are logical volumes ) : ...
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1answer
178 views

What are the options for a HA system?

I'm looking into creating a HA Linux machine for my client's website. What are the main options I have, or a place/article where I can find out more? I would LOVE if it was a single-image, too, so ...
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1answer
156 views

What FLOSS linux software should I use for high-availability on an FTP server on vmware? [closed]

I don't mean this as an opinion-based question. I want to know if my assumption is correct to use a network-oriented tool (keepalived) as opposed to a cluster-oriented tool (heartbeat) in a scenario ...
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1answer
116 views

Setup Galera Cluster with two servers

Can I Create Gallera Cluster with two servers ?? Actually I have 6 servers: 2 Server for Load Balancer 2 Server for Apache Or anyone here can suggest me how to create High Availability Web Server ...
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1answer
50 views

Website failover across internet connections

Requirement For a network having 4 static IP internet leased line connections linked to hosting a website. What are the current strategies one can apply to ensure high availability in case of ...
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1answer
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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3answers
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What is the difference between Anycast and GeoDNS / GeoIP wrt HA?

Based on the Wikipedia description of Anycast, it includes both the distribution of a domain-name-to-many-IP-mapping across many DNS servers as well as replying to clients with the most geographically ...
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304 views

Haproxy load balancing TPS lower than single node

I have 2 apache2 servers running in the back end and have a haproxy between them and the clients. If I bench tested anyone of these apache2 severs with ab i get north of a 1500TPS however when I bench ...
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Multiple data centers and HTTP traffic: DNS Round Robin is the ONLY way to assure instant fail-over?

Multiple A records pointing to the same domain seem to be used almost exclusively to implement DNS Round Robin as a cheap load balancing technique. The usual warning against DNS RR is that it is not ...
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1answer
702 views

Corosync dynamically add node

I have been experimenting with Pacemaker & Corosync for a HA setup. I installed it on two Ubuntu 14.04 Linode's and after a lot of back and forth on outdated config examples and tutorials, managed ...
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1answer
4k views

Where are Nagios Availability-Report files stored?

How to access Nagios Availability-Report files to retrieve "UP Time Percent" and so other information about Hosts and Services? I know It can be accessed through Nagios CGI but I want to use it on a ...
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1answer
3k views

is it possible to synchronize the states of TCP proxies in real time (for real-high-availability of SLB)?

Consider that there are two server load balancers working in the tcp proxy mode (e.g., for L7 load balancing). Is it possible to synchronize their states in real time so that they can be a backup for ...
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1answer
1k views

SQL Server 2012 Mirroring / AlwaysOn - need for SAN?

There appears to be a great deal of conflicting information about whether or not SAN is required for a Sql Server 2012 Mirroring setup. I currently have an Active-Passive-Witness SQL 2008R2 setup ...
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1answer
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 ...
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1answer
174 views

What's the best way to sync folders across 03 or more webservers? [closed]

I have 03 servers and I want to sync some folders across them. I'm using DRBD + OCFS2 for a year or so, but it doesn't support more than 02 servers right now. I read about GlusterFS and CEPH, but ...
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3answers
225 views

Website high availability without load-balancer?

I'm considering options for changing a 'high availability' website that provides a service via an https api. The current setup is: Two self-contained VMs, from different cloud providers (AWS and ...
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428 views

Using ZFS head node as database server?

I'm using a dual-head ZFS-backed NAS for high availability cluster shared storage, based on Nexenta's recommended architecture as seen here: The disks in 1 JBOD will store the database files for a ...
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2answers
863 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
101 views

Should each machine in a high availability cluster have same time zone?

I'm curious if people with experience think it makes sense to give all machines in a replication cluster the same time zone and time regardless of physical location to help ensure that dates are ...
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1answer
105 views

Multi domain server with dedicated SSL's HA

I am hosting a server with 150 domain names (websites), each of the ssl's requere dedicated IP address. So server windows 2008, with 150 IP addressees and 150 websites. I need to have high ...
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1answer
238 views

Shared storage solution for Debian Wheezy [closed]

I need to setup a new infrastructure which provides high available shared storage between debian servers. Our current solution is a "clustered DRBD NFS solution". We have setup 2 virtual file ...
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1answer
591 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 ...
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3answers
98 views

Webserver failover with VMs on Two esxi 5.1

I have two server on datacenter with two websites abc.com, cde.com, and my model : ESXi 1 NIC1 113.11.11.11 from ISP NIC2 192.168.1.1 cross connect NIC2 ESXi2 VM CentOS6 ...
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Is there a way to force heartbeat to add new ip addresses to the system without a full restart?

We utilize heartbeat for High Availability. I'd like to add an additional ip address to the heartbeat cluster, but I don't want to do a full restart of the cluster in the process. Is there a signal ...
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3answers
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Does it work to run mysql with the data directory on a CephFS mount?

We have a database cluster that uses MySQL on DRBD with Pacemaker+Corosync, which is great. My question is whether it is possible (and whether anyone has been successful) to mount a CephFS drive to ...
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1answer
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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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388 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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1answer
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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
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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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326 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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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
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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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189 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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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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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
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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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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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 ...
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491 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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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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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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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 ...