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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How to safely store data and DBs on Kubernetes (or similar) on DigitalOcean

It boils down to setting up a private cloud on something like Digital Oceans versus another hosting solution like GCE or AWS. The latter have redundant data stores that can be safely used as volumes, ...
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21 views

Best Reliability for Linux OS: FakeRAID, SoftRAID, or No RAID

I'm tasked with building a highly-reliable, unmanned industrial PC that will withstand unplanned power outages. A UPS will be used where possible, but realistically we know that many of these units ...
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0answers
8 views

How do mirrored virtual disks get distributed in a 4 disk storage pool?

I have a Windows 2012 R2 server with 4 3TB drives. I had to upgrade after one of my JBOD disks failed and luckily I had backups to recover from my storage pool of 2-3TB and 2-1.5TB drives with 4 ...
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1answer
37 views

Backup DNS servers for a domain name - optimal configuration and troublehooting

Let's say we have these name servers for 1 domain. ns.1.com ns.2.com ns.3.com ns.4.com backup-ns.1.com backup-ns.2.com How can I know which NS responded to this specific query, for example using ...
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2answers
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Is it possible to have a secondary managed DNS provider to quickly delegate to when DDOS attack on our *primary* external DNS provider happens?

So our DNS provider, every so often, experiences DDOS attacks on their systems that causes our front-facing web sites to go down. What are some options in terms of reducing dependency on a SINGLE ...
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2answers
37 views

Fallback between datacenters

What is the best way to do a fallback between datacenters. We have a dedicated server in one of the data centers and as our traffic increased i wanted to add more then backup i wanted redundancy and ...
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0answers
22 views

keepalived should vote more relaxed, is raising garp_master_delay and/or advert_int the solution?

Im using keepalived on two machines. The one being the master establishes an ipsec tunnel. Sometimes (once a month or less) the vrrp packet was missed, and the backup takes over, establishes the ipsec ...
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1answer
33 views

Need some clarification on a NIC functionality on a Dell Poweredge r610

Quick question. I'm trying to understand the NIC functionality of this server. NIC specs from manual: My question is, do the two broadcom controller chips provide fail-over redundancy? For example, ...
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2answers
137 views

VM migration and IP address

When a VM offering a service is migrated to a different server is it an important requirement from the client applications point of view to retain the same IP the VM had before ? For long lived TCP ...
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1answer
129 views

How to setup redundant ejabberd servers?

I currently have an ejabberd server running at domain A. It has a bunch of users with accounts like xyz@A. I want to setup alternative servers so that if A is down, clients can transparently use ...
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1answer
32 views

Is it feasible to switch DNS A records to point to a backup provider in case of failure?

Is it feasible to switch DNS A records to point to a backup provider in case of failure? Instead of relying on one provider/datacenter. I know there is a lag due to ISPs caching the records, but ...
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2answers
364 views

NTP: How to establish redundant solution for NTP servers?

In my company's infrastructure there are 5 data centers in remote locations. In each remote location, there's a pair of servers which hold DNS and NTP services and are configured on each one of the ...
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1answer
30 views

Distributed (serverless) Database System [closed]

I've currently a setup where 10 database clients access one (Postgres)-SQL server on the same network. The applications have a very low db footprint. They do load a few tables upon startup and do ...
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2answers
52 views

Common Practice for router setup in a business [closed]

At the company that I'm working for, we have one router (SonicWall TZ 210) and it occasionally go down during business hours. All I have to do to bring it back up is to power cycle the router but ...
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1answer
86 views

Achieving File Server Redundancy

We are in the process of moving all servers (or virtualising physicals) into a central datacenter connected via MPLS. Currently we are fully redundant on most aspects - RDS Farms, SQL Clusters, ...
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2answers
85 views

Creating a redundant environment with ONLY 2 servers (so without a third server that handles the load-balancing) [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 ...
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1answer
200 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
108 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 ...
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2answers
91 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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1answer
118 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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0answers
59 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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35 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 ...
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1answer
590 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 ...
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1answer
53 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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1answer
568 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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2answers
80 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 ...
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83 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
298 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 ...
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2answers
312 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
35 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 ...
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3answers
2k 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
48 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 ...
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1answer
117 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 ...
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171 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 ...
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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
301 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 ...
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0answers
1k 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
71 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
114 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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1answer
72 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 ...
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3answers
2k 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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5answers
1k 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 ...
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1answer
142 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 ...
3
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1answer
319 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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5answers
1k 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 ...
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2answers
33 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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1answer
1k 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 ...
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2answers
87 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 ...
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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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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 ...