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Questions tagged [redundancy]

In engineering: 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.
In information theory: It is the number of bits used to transmit a message minus the number of bits of actual information in the message.

62 questions
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How long will an unused hard drive store its memory?

Possible Duplicate: How much time until an unused hard drive loses its data? I have a broken laptop, and it's the motherboards fault that it can't turn its power on. The laptop has been stored for almost 2 years now and I'm about to get its hard…
winona
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Can Linux scrub memory?

Does Linux have a mechanism to "scrub" memory? e.g. testing the memory and marking areas as dirty if they fail so that the system can continue to operate "safely" even with bad ram chips installed?!
Waxhead
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Is a home NAS reliable to keep your data on (no other backups)?

The question came up while I was thinking to move some data (e.g.) pictures, old but important other data solely to the NAS (private use, no business level). My NAS is a simple 2 disk RAID system. I know that a RAID is not a backup system as it only…
Samuel
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What is the practical value of redundancy in zip files?

How is redundancy implemented in zipping, and how do I benefit from it? I'd assume it consists of something like storing the lookup tables twice so a single defect does not invalidate the whole rest of the file. Regarding the use case, possibly when…
mafu
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Software Alternative to RAID for Home Use

I have a ton of data that I've been keeping 2 complete copies of between my Desktop and Laptop for a couple years now; I figure its about time to buy some more drives and make sure I don't lose any of it due to drive failure and whatnot. At first I…
Jeff Dalley
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Linux software RAID robustness for RAID1 vs other RAID levels

I have a RAID5 array running and now also a raid1 that I set up yesterday. Since RAID5 calculates parity it should be able to catch silent data corruption on one disk. However for RAID1 the disks are just mirrors. The more I think about it I figure…
Waxhead
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4 answers

RAID-like filesystem for heterogeneous set of hard disks

During the last years I have accumulated a quite heterogeneous set of hard disks of different sizes and speeds for storing my private data. I'm planning to put them in a self build Linux filer to reduce the hassle of replicating local data manually,…
Moredread
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How does RAID 1 determine whether a disk is corrupted?

I've built a RAID 1 array of 2 disks, A and B. That means that every bit on A is equal to a bit on B. If one disk fails, I can safely retrieve my data from the other disk. But then I started wondering: How true is this? Let's say a bit 1 on A reads…
Einar
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1 answer

Adding redundancy to unused space of a DVD

I have a 900 MB file and I'd like to safely archive it on a DVD. As you can see 3/4 of the space will be empty. Besides the obvious possibility to just write the same file with 4 different names is there any other (more useful) solution? Of course…
vbence
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Is there a type of redundant disk filesystem that allows for some loss of data?

I'm building a media server on a budget. Currently, the design is to have four 500GB disks in a JBOD-type format giving me one large 2TB store. The problem is if any disk fails, I lose the whole array's data. I'd like to avoid dedicating a disk to…
Thomas O
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8 answers

RAID 1 mirroring to more than two drives?

I do not trust any RAID types for home use. I've got 2 Terabytes of Data that I want to copy (duplicate) to about 4-6 drives for redundancy so that I will never lose these pics and videos I've created of my family. I know that 100% failure…
WeDoTDD.com
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Proper network architecture for fault tolerant multi WAN multi building WLAN setup

I need help with deciding the correct network architecture for a guest WLAN deployment. We have 3 buildings, and each of them has its own LTE router (Mikrotik RB411U) connected to an Ubiquiti EdgeRouter PoE (to eth0). The buildings are connected…
AnttiP
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Adding parity to backup dvds

I am backing up about 1.8GB of pictures to a dvd, but because over half the disk is free, I would like to add parity of the free space so that data can be read even after some data corruption has started over time. i know of dvdisaster, but i cant…
Daniel
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2 answers

Automatic failover of two internet connections Mac OS X

Is there any way to set up an automatic failover for internet connections within Mac OSX? Basically the main connection would be ethernet or wifi and if the main connection goes does, it would switch to a 3G mobile phone or another Wifi connection.
Ruben
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Do par2 files have inner redundancy for bitrot on recovery blocks?

I just found a wonderful looking tool named par2. It can generate error correction blocks for any file I want and use those to later recover corrupted data. I started to wonder if there is any redundancy on the par2 generated recovery block files…
The amateur programmer
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