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Questions tagged [high-availability]

High availability is an architectural consideration often involving degrees of redundancy to insure availability in case of system or component failure.

High availability is an architectural consideration often involving degrees of redundancy to insure availability in case of system or component failure. Highly available systems are commonly implemented in situations where the risk outweighs the cost.

Best practices such as change control, standardized procedures, and monitoring can also enable high availability.

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Load balancing Apache on a budget?

I am trying to get my head around the concept of load balancing to ensure availability and redundancy to keep users happy when things go wrong, rather than load balancing for the sake of offering blistering speed to millions of users. We're on a…
Industrial
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RabbitMQ - How I do configure servers for zero-downtime upgrades?

Having read through the docs and RabbitMQ in Action, creating a RabbitMQ cluster seems straightforward enough, but upgrading or patching an existing RabbitMQ cluster seems to require the whole cluster to be restarted. Is there a way to combine…
Terence Johnson
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what cluster management software to use for linux?

I have found the following cluster management software tools: pacemaker (clusterlabs.org), - original a Heartbeat project, focus for high-availability, will be in the next debian version openqrm (openqrm.com), - web gui - broader usage, a A site…
yvess
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Avoiding SPOFS with GlusterFS and Windows

We have a GlusterFS cluster we use for our processing function. We want to get Windows integrated into it, but are having some trouble figuring out how to avoid the single-point-of-failure that is a Samba server serving a GlusterFS volume. Our…
sysadmin1138
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How can I load-balance a load balancer?

I'm about to convert a single-server single-database web application into a physically distributed high-available configuration with servers on two physical locations (for now). Now, obviously, I need a load balancer (more like a reverse proxy in…
Nikolai Prokoschenko
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Keepalived for more than 20 virtual addresses

I have set up keepalived on two Debian machines for high availability, but I've run into the maximum number of virtual IP's I can assign to my vrrp_instance. How would I go about configuring and failing over 20+ virtual IP's? This is the, very…
cvaldemar
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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 replicated bricks between the servers (since you…
cbaltatescu
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The downsides of using nginx as a primary web server?

I've seen millions of websites using nginx as a proxifying webserver working together with Apache. But I've seen very few servers running nginx only as their default webserver. What are the main downsides of such config? I can see some: Inability…
Vladislav Rastrusny
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How to design/ensure high-availability of web servers?

I have been given a dedicated server by 1&1 internet, which has two hard drives in a RAID1 configuration. I expected this would be good enough as if one disk fails, the other can take over until the damaged one is replaced. However on two ocassions…
volume one
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Mathematically, how to calculate an uptime percentage based on a number of nodes and their respective uptime percentage?

This question is more of a math question than a server question, but it is strongly server related. If I have a server that I would be able to guarantee 95% uptime and I would put that server in a cluster of 2, how much would the uptime be then?…
Jeroen Landheer
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High server availabilty for a small business

After having a bit of scare with a server that wouldn't come up one morning, the higher ups have decided that the business needs a high availability / fail over setup. We have 5 main servers (4x Linux, 1x OpenBSD) all of which need to be running for…
Matthew
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What's the difference between keepalived and corosync, others?

I'm building a failover firewall for a server cluster and started looking at the various options. I'm more familiar with carp on freebsd, but need to use linux for this project. Searching google has produced several different projects, but no clear…
hookenz
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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: 83ca112086600faacab2f157bc5a9324f7bd7f77 build by…
favadi
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Looking for a recommendation on measuring a high availability app that is using a CDN

I work for a Fortune 500 company that struggles with accurately measuring performance and availability for high availability applications (i.e., apps that are up 99.5% with 5 seconds page to page navigation). We factor in both scheduled and…
Tim Reddy
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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 for our domains through our registrar…
Jack M.
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