Redundancy is the duplication of critical components or functions of a system with the intention of increasing reliability of the system, usually in the case of a backup or fail-safe.

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Creating a redundant environment with 2 servers [duplicate]

First of all, i'm sorry if this question has been answered before, but i've been searching for a while now and couldn't seem to find (or understand) an answer. So, i have two physical servers with ...
3
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1answer
136 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
34 views

ensure “switch redundancy” on a network

I'm struggling in connecting two Windows 7 PCs (each with a 2 port Intel NIC) via two complete redundant paths. And I want to make it transparent to the services on that system. I was thinking on ...
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1answer
29 views

Host using Linux bond mode 1 (active/backup) connected to 2 x independent switches

I have a host using Linux bond mode 1 (active/backup) connected to 2 x independent switches. Please can someone confirm if this is possible for successful failover between NICS or do I have to ...
3
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3answers
973 views

Evaluating uncorrectable ECC errors and fallback methods

I run a server which has just experienced an error I've not encountered before. It emitted a few beeps, rebooted, and got stuck at the startup screen (the part where the bios shows its logo and begins ...
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2answers
65 views

What's the best method to achieve full redundancy in a dedicated server? [closed]

I've been reading about full redundancy to achieve almost if not 100% uptime for your mission critical applications (handling financial data) running in a dedicated server, but I still can't wrap my ...
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0answers
18 views

Intel server SC5300LX+SE7520BD2 won't boot after removing a second PSU

I have an intel server SC5300LX+SE7520BD2 with 1+1 redundant PSU (Delta electronics C46098-005). As one of the PSU had an amber led lightning, I decide to check the part-number and I did this by, ...
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0answers
18 views

How setup redundant static ip Internet for outages

We host an iis 7.5) windows site on a comcast business static IP (in office). the internet goes down sometimes and I;d like redundancy. I cant find the proper way to add a second internet ...
3
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1answer
82 views

SSD's in servers, best practice redundancy?

So some might say Im an experienced infrastructure architect guy and have been putting together server farms, storage subsystems and networks for a number of years in datacenter environments ...
0
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0answers
25 views

Speed up EIP reassignment

I have a real-time application running on an Amazon EC2 instance. I'd like to implement master/slave redundancy with a VPC, a second instance and keepalived. So far it's working reliably, but in the ...
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2answers
54 views

How many SSDs are needed to assure redundancy? [closed]

If we consider, hypothetically, that a server farm is being designed to have 100TB of storage using solid state drives (SSD), each with 250GB each. My question is how many SSD are needed to ensure ...
0
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1answer
40 views

How to setup redundancy for AWS Elastic Load Balancers?

In the spirit of redundancy and fail-over, I would like to know some strategies on setting up AWS Elastic Load Balancers for DR, that is, if this is really an issue? (A single ELB would LB traffic to ...
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0answers
19 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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2answers
55 views

Internet connection redundancy with 2 ISP

Setup is 1. One Linux server running web server and ftp server. 2. Two ISP which provided a range of public IP address 3. From the client(browser) side we can set only one of IP/domain name as ...
0
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2answers
86 views

UPS systems in parallel for redundancy and/or capacity, generator as backup, ATS,

I am about to upgrade our server room's power plan and would kindly ask you for your help with a proper, optimal design / advice on "good practice" approach. Please note that our business is small, ...
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0answers
20 views

several domain controller logon

I've got two domain controllers. The master is DC01 and slave Fil01. I got that problem, that some computers logon over the slave dc and not the master. How can I set the order or prevent them on ...
2
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5answers
836 views

Self-healing archive file format with redundancy

When I used RAR, I had an option to add some extra recovery data in order to be able to cope with a not-perfect medium (think floppy disks). It saved my day several times, specially when dealing with ...
9
votes
3answers
597 views

How to make redundant load balancers?

I understand that the purpose of load balancers is to balance load between your servers and keep track of instance health, etc. But what if load balancer itself fails? How do you set up redundant load ...
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1answer
42 views

How I do to run only a software in more than one computer? [closed]

I need to run a unique instance of a software in more than one computer, how I do this without a centralizer server? For example: 4 computers interconnected by the local network, 2 of then has "the ...
2
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2answers
101 views

How do you ensure that two data network links have no SPOF?

How do you ensure that two data network links have no SPOF (Single Point of Failure)? We are working on a datacenter network connectivity and need to ensure that there will be no SPOF. We will have ...
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1answer
60 views

Setting up a small network with a redundant WAN setup

Asked on the network stack but referred here, partly because lower grade equipment. Small office and we are trying to piece together a network with our two wans (diff ISPs) a switch and a few ...
4
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4answers
176 views

Achieving Five Nines

I am building a web application where uptime is key. I understand that 100% uptime is not realistic but I would like to achieve five nines. I'm unsure as to the most prudent way to accomplish this. ...
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0answers
105 views

How to setup failover and load balance when two WAN links are available each one with a single public IP

I have read the question in here but I feel it's not exactly my setup. I have two physical ADSL modems (not a single one like as in the picture of ...
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0answers
112 views

Layer 3 switch redundancy solution (with vlan's, stp)

So basicly I have a setup which I want to get to work but i'm unable to. It's possible I am overseeing a lot of things but let's get to it anyways. The current situation is a network with 4 switches ...
3
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1answer
186 views

Howto do VCSA redundancy?

We are currently in the process of setting up a new VMWare environment which is now only in lab phase. We are studying the possibility to have a vCenter cluster with an active and a ...
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3answers
247 views

How common is it to use additional dedicated servers for redundancy?

I'm new to handling the infrastructure for production service deployments. My intuition tells me that if I want to have my service be "up" as much as possible and yet can only afford say 2 dedicated ...
21
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5answers
2k views

How to protect against loss of server on a budget

I'm a small company on not much budget providing websites and databases for charity and not-for-profit clients. I have a few Debian Linux VPS servers and ensure I have daily backups to a different ...
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1answer
155 views

Teaming the 2 ports of a hp 361T pcie Dual port GB Nic [closed]

We have a network with two switches stacked for redundancy. We have a HO 36LT PCI-e Dual port NIC and an Intel x520 10GbE port adapter. I want to be able to assign one IP address for both ports. I ...
2
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1answer
83 views

“Hot data” and erasure coding: how to know if it is efficiently handled?

It is well known that erasure coding adds extra complexity because of encoding and decoding operations. Due to this drawback, most of cloud services recommend to use data replication for hot data and ...
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2answers
4k views

Redundant NFS on Amazon EC2

I'm interested in building two fault tolerant/redundant NFS servers with failover at Amazon EC2. I'm familiar with tools/technologies like DRBD, Heartbeat, etc. Does Amazon provide any specific way of ...
6
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3answers
3k views

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 ...
1
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0answers
543 views

Creating redundant IPSec connections using OpenSwan

I have a linux (netkey) instance with openswan installed, the instance has two connection to the same IPSec peer that needs to act as redundant connections. both connections' properties are the same ...
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1answer
60 views

What are common server architectures to build a reliable website [closed]

Sorry, if my question looks too general, but I am looking for an answers to specific problems that I listed below and would appriciate any help. My website is growing in popularity and I would like ...
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1answer
53 views

Rapid failover from one data center to another when the first goes down?

I'm building a global CDN and have a DNS service that will direct customers to the closest server. However I need rapid failover if one of the data centers e.g. Germany goes down users need to be ...
12
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4answers
896 views

Is there any value in protecting both rack power feeds with their own UPS?

I've done some looking and have not found a satisfactory answer to this question. When is it necessary or suggested to use an independent UPS (on it's own mains branch circuit) for each power feed to ...
44
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7answers
7k views

Probability of Blade Chassis Failure

In my organisation we are thinking about buying blade servers - instead of rack servers. Of course technology vendors also make them sound very nice. A concern, that I read very often in different ...
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1answer
107 views

Does chassis mid-plane provide load balancing for power supply

I am new to blade chassis management, and i want to know what is the purpose of mid plane apart from connectivity. Does it provide load balancing among the power supplies. If so does that mean it ...
7
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2answers
3k views

One server, Two APC UPS on redundant power supplies : How to trigger shutdown?

I have a server racked and its redundant power supplies plugged in two APC Smart-UPS 3000 XLM. Each UPS is connected to two different mains power sources. Two instances of apcupsd are running, each ...
3
votes
1answer
1k 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 ...
8
votes
5answers
976 views

Hot spare host vs cold spare host?

We have several hosts where we have an identical hot spare host, which is patched and updated so it is very close to have to same software and config. In case of failure the network cable is switched ...
2
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1answer
806 views

HyperDB Configuration Master/Slave

Running on server 2008 R2 IIS 7.5, with a MySQL Master/Slave (also on server 2008 r2), and WordPress 3.7. Is it ONLY compatible with wordpress 3.5.2? If that is so is there any other plugins to allow ...
0
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1answer
615 views

CARP Virtual IP does not ping in virtualized environment

We have three physical machines with SmartOS on them in a LAN. Two of them, 10.40.0.30 and 10.40.0.240 are hypervisors with two pfSense-based virtualized gateways on them. These gateways have ...
0
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2answers
30 views

Providing redundancy for processes on different servers [closed]

Say I have for example 5 physical machines with similar resources (CPU speed, RAM and storage) named s1, s2, s3, s4 and s5. If I have a processes running on s1 but then s1 fails somehow, how can I ...
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2answers
74 views

Implementing DNS Redundancy - Web Hosting

After our domain registrar/name server host went down we have found that DNS is a major single point of failure as its also taken down all of our email (Office365), web, hosted services etc.. I want ...
36
votes
16answers
37k views

Is Round-Robin DNS “good enough” for load balancing static content?

We have a set of shared, static content that we serve up between our websites at http://sstatic.net. Unfortunately, this content is not currently load balanced at all -- it's served from a single ...
2
votes
4answers
919 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 ...
2
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3answers
8k views

How do you set up redundant servers?

To the sysadmins out there, I'm trying to get an idea about how you go about maintaining redundant servers for small projects. The modest number of servers in my mind is two, and three main essential ...
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3answers
576 views

IRC Services with failover support?

I run a single server (call it 'server A') IRC 'network', and thank to the generosity of some friends, I have been given a second server ('server B') that I can run an IRCd on in order to provide ...
1
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2answers
785 views

Redundant routing (active/backup) on linux

I'm currently trying to setup a redundant routing on RHEL 5. The target goal is to have a primary route to a subnet and a backup route to that subnet, to be used only if the gateway of the primary ...
2
votes
1answer
432 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 ...