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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24 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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17 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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38 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 ...
9
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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 ...
2
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4answers
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Is it possible to use mixed 110V / 208V power on a single server with dual power supplies?

Is it possible to run a dual power supply server with one PS plugged into 110V, and the other power supply plugged into 208V? We've asked the vendors and they say they've never tested it or some other ...
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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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1answer
125 views

How to Add a Secondary Server, Correctly

Just wondering if a network of approximately 15 users has only 1 Server Running Windows 2003 and wanted to add a "secondary server" so that in the event the "primary" fails for any reason the ...
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23 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, ...
0
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1answer
54 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
869 views

“Simple” Failover to a Geographically Separated Server?

I've been reading about DNS failovers and a bunch of other technical terms however I'm a bit of a newbie in this so it all sounds Greek to me. Basically here's what I just need: I have two shared ...
12
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2answers
6k views

Alternatives to Dell's mirrored SD card module for booting a small OS from flash?

Dell offers an add-on hardware card for some of their servers that provides a poor man's RAID1 between two SD cards (one card gets all the reads until it dies, writes are mirrored) for booting a ...
12
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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 ...
4
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1answer
144 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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2answers
159 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
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 it'...
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2answers
388 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
34 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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1answer
191 views

Consistent Reliable Messaging

Im working a new project, Im currently deciding between flume & scribe for messaging systems... ( most probably sent to logs or hadoop ) I cannot lose a message ever.. What are your thoughts ...
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3answers
725 views

How much power draws a redundant PSU?

One supermicro enclosure comes with "3 SP382-TS 380W Power Modules for a total of 760W". 2x380W = 760W, okay, but there are 3! So where is the missing third 380W equalling to 1140W?? Is it hot-...
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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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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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1answer
96 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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86 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
204 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
140 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
111 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
93 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
61 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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37 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 provider/...
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1answer
682 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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2answers
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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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1answer
668 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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88 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
317 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
324 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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36 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
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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 ...
13
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3answers
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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 ...
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 ...
1
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1answer
129 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
185 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. ...
0
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0answers
176 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
334 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 standby/mirrored/...
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3answers
254 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 ...
22
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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
315 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 ...