Questions tagged [redundancy]

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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Can't access ZFS formatted drives (redundant setup)

I keep my important data on 2 drives that are mirrored (I think that is the correct terminology) in a machine running Ubuntu 12.04 LTS. Today, I was unable to access any of the data and 'sudo zpool ...
Damon Sisk's user avatar
6 votes
4 answers
5k views

If a RAID controller fails, does it disrupt service until it's replaced?

If I have 2 drives in a RAID 1, and the Raid Controller fails, does that mean the websites on the server will have downtime until the controller is replaced? Or does everything still carry on as ...
Winker's user avatar
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-1 votes
1 answer
116 views

How many drives can fail in an Xserve RAID in RAID 0+1? [closed]

I’m torn between what I know (or think I do) and what Apple’s documentation states. The hypothetical setup I’m considering is what is described as RAID 0+1 in Apple’s documentation for the Xserve ...
kumowoon1025's user avatar
0 votes
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39 views

How do region based services with a single backing database work to improve redundancy or load balancing?

I've used services where there are multiple application servers spread out throughout US, at least I have to assume because I could explicitly use urls like EastUS.email.Com or WestUS.email.Com or ...
Sidney's user avatar
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2 answers
30 views

Is it possible to boot from a DAS device with read-only access?

Without boring you with the details, I'd like to run two servers from the same DAS. One server would be the primary server and would have read / write access to the DAS. The other server will be the ...
Dan Truitt's user avatar
2 votes
2 answers
2k views

How to manage redundant ISPs with dynamic DNS

I'm trying to make my small business network a bit more robust by adding a fallback ISP. What I can't figure out is how to manage the DNS for inbound connections. A simplified view of my network looks ...
Dominic P's user avatar
  • 497
3 votes
1 answer
453 views

Openstack redundant architecture on three servers

I would like to deploy an Openstack architecture on three (super)servers in a way that if one of server is down the Openstack infrastructure is still functionning. What is the best way to deploy ...
SwissFr's user avatar
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9 votes
4 answers
645 views

Redundant Power Supply Sloshing (If sloshing is the right word)

I have a Supermicro Redundant Power Supply with two units in it. I also have two UPS units, one for each of the Power Supplys. I was watching the LCD on the UPSs for the watt usage. The total watts ...
xriri's user avatar
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1 vote
2 answers
330 views

Methodology to find a "stable" IP addres within some ISP's AS network

Some definition(s)/meaning(s): Stable IP address - a host within Internet Service Provider (ISP) Autonomous system (AS) network, replaying to ICMP type 8 echo request. Genesis: My routers monitor ...
Michal Sokolowski's user avatar
0 votes
1 answer
144 views

Connect switches using SFP connectors or uplink

In our environment we have 2 server rooms. One is our primary server room where internet is comming in and where our main servers are located. Then we have a secundary server room where our backup ...
Mivaweb's user avatar
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8 votes
3 answers
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Increase reliability by partitioning disks of different size?

I understand ZFS would prefer all disks carrying the same size. However, in the case that I have two disks with different size (1TB and 1.5TB), I'd like to have certain redundancy, but not mirroring. ...
python152's user avatar
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-2 votes
3 answers
2k views

Is it possible to have multiple storage servers in a failover cluster?

I'm familiar with setting up RAID arrays and am running a few in my home environment. I was wondering if it's possible to have multiple storage servers in a failover configuration. What I hope to ...
Mephy's user avatar
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1 vote
5 answers
416 views

Server Network Redundancy and Availability

If I have one server with RAID 50 or 10, then data is distributed among hard drives in case one fails. Can the same be done across multiple servers. Can data be distributed among multiple servers, so ...
SJ Johnson's user avatar
0 votes
1 answer
486 views

Best approach for redundant storage DAS/SAN

We've always used DAS storage (which as per Dell standards) have multiple controllers for redundancy, multiple PSUs etc. However, in the event of full hardware failure (which may or may not be likely) ...
PnP's user avatar
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0 votes
1 answer
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OpenStack Redundant Ceph/Cinder Storage Architecture

Hello Serverfault community, I'm currently designing an OpenStack cluster. The part where I'm currently stuck is the Storage Architecture. I thought of building two redundant Ceph clusters in ...
Phinitris's user avatar
1 vote
1 answer
314 views

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, ...
Sarke's user avatar
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0 answers
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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 ...
EnemyBagJones's user avatar
-1 votes
1 answer
80 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 dig?...
Mindaugas Bernatavičius's user avatar
14 votes
2 answers
3k views

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 ...
Emmel's user avatar
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2 answers
227 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 ...
disi's user avatar
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-1 votes
1 answer
220 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, ...
user1330287's user avatar
-1 votes
2 answers
4k 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 ...
Manohar's user avatar
  • 229
5 votes
1 answer
977 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 ...
knarf's user avatar
  • 141
0 votes
1 answer
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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'...
Sarke's user avatar
  • 451
5 votes
2 answers
4k 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 ...
Itai Ganot's user avatar
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-1 votes
1 answer
90 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 ...
Hhut's user avatar
  • 133
-5 votes
2 answers
64 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 ...
Kirk's user avatar
  • 3
2 votes
1 answer
722 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, ...
PnP's user avatar
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0 votes
2 answers
411 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 ...
Lars Behrens's user avatar
3 votes
1 answer
410 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 ...
Digital ink's user avatar
1 vote
2 answers
4k 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 ...
adamjth's user avatar
  • 11
-3 votes
2 answers
578 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 ...
officeboi101's user avatar
0 votes
1 answer
773 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 ...
Hhut's user avatar
  • 133
3 votes
1 answer
4k 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 (...
tomstephens89's user avatar
0 votes
1 answer
171 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 ...
Iskren's user avatar
  • 241
6 votes
1 answer
6k 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 ...
ElHaix's user avatar
  • 269
-5 votes
2 answers
342 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 ...
Francisco Maria Calisto's user avatar
0 votes
2 answers
1k 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 ...
user2627240's user avatar
2 votes
2 answers
1k 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, ...
Charlie's user avatar
  • 23
0 votes
0 answers
51 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 ...
FV-Photography Mannheim's user avatar
40 votes
3 answers
21k 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 ...
Sherzod's user avatar
  • 511
-2 votes
1 answer
57 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 ...
Only a Curious Mind's user avatar
1 vote
1 answer
554 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 ...
TrustNoOne's user avatar
0 votes
0 answers
689 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 ...
Ciberth's user avatar
23 votes
5 answers
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 ...
artfulrobot's user avatar
  • 3,099
-1 votes
1 answer
830 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 ...
DavyGravy's user avatar
  • 159
2 votes
0 answers
3k 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 (...
Amir's user avatar
  • 21
-1 votes
1 answer
106 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 ...
Temnovit's user avatar
  • 1,127
4 votes
1 answer
357 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 ...
denaitre's user avatar
-1 votes
1 answer
170 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 ...
Mark172's user avatar
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