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.
Questions tagged [redundancy]
294 questions
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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 alternative servers B and C (thus, while still using…
knarf
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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 servers in that location to get DNS and NTP calls…
Itai Ganot
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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 listing information) with the error:
Node0:…
Zhro
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ZFS RAID0 pool without redundancy
I created a ZFS pool on Ubuntu 14.04 without specifiying RAID or redundancy options, wrote some data to it, rebooted the machine and the pool is no longer available (UNAVAIL). I don't have the exact error to hand but it mentioned that there was not…
codecowboy
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How far should we take the N+N redundancy craziness?
The industry standard when it comes from redundancy is quite high, to say the least. To illustrate my point, here is my current setup (I'm running a financial service).
Each server has a RAID array in case something goes wrong on one hard drive
....…
Brann
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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 old CDs (scratched or when the reflective layer…
Steve Schnepp
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Providing high availability and failover using MySQL on EC2
I would like to have a highly-available MySQL system, with automatic failover, running on Amazon EC2 instances.
The standard approach to solving this is problem Heartbeat + DRBD, but I've found a lot of posts suggesting DRBD doesn't work on EC2,…
crb
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Redundant links from Router to Switches
With a setup of two NICs on a server into two different switches where each NIC has a different IP (But both on the same network), and then the switches to the router. How would I configure the two ports on the router to be redundant so that one…
Kyle Brandt
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Plug single PSU into two different power sources
We have a rather uncommon situation:
We have a server in a computer center. Its got not enough spare space to put in a redundant PSU. Nevertheless, we want to attach the single PSU to both existing power sources, because it happens fairly often (in…
roesslerj
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Which is more standard in large enterprises: RAID5 or RAID10?
Which is more standard in large enterprises: RAID5 or RAID10?
Hugh Perkins
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"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 erasure coding for cold data.
For example, from…
denaitre
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Sharepoint - one way sync to a second SP server for standby/backup
Using MOSS 2007 on SQL server 2005 is there any way to do a "one-way" synch of data from a production server to a standby server? This would be a one-way process only, and can happen daily rather than in real-time. The standby server won't be used…
DrStalker
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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 R2 back end storage servers running SMB 3.0 shares,…
user214324
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Redundancy level on a per file basis with BTRFS?
I would like to have one storage pool with multiple disks.
Raid5 for metadata of course. But for user-data I would like to set the level of redundancy on a per file or per subvolume level.
Can BTRFS do this?
In ZFS there is a 'copies' attribute that…
TilmanBaumann
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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.
My preliminary plan was to have the web app running…
user102878