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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Is Round-Robin DNS “good enough” for load balancing static content?

We have a set of shared, static content that we serve up between our websites at http://sstatic.net. Unfortunately, this content is not currently load balanced at all -- it's served from a single ...
43
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7answers
3k views

Probability of Blade Chassis Failure

In my organisation we are thinking about buying blade servers - instead of rack servers. Of course technology vendors also make them sound very nice. A concern, that I read very often in different ...
11
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8answers
3k views

Load balancing Apache on a budget?

I am trying to get my head around the concept of load balancing to ensure availability and redundancy to keep users happy when things go wrong, rather than load balancing for the sake of offering ...
10
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9answers
13k views

Correct way to set up DNS primary/secondary/… for redundancy and latency reduction?

I thought DNS primary/secondary for redundancy purposes was straightforward. My understanding is that you should have a primary and at least one secondary, and that you should set up your secondary in ...
4
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2answers
1k views

Network Redundancy Example

Looking for help filling in how redundancy in the following model might work: I believe my Datacenter will give me redundant gateways with two hand offs (going to have to talk to the more about ...
1
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1answer
613 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 ...
3
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4answers
11k views

Split your DHCP scope among multiple servers?

I want to implement a redundancy solution. I have two subnets all windows XP machines - each with their own DHCP server - joined by a bridge. Currently - all machines get DHCP leases from the one ...
13
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21answers
4k views

When is RAID worth the trouble?

In our shop we're faithfully using RAID in all our workstations, probably just because that seems to be the way it ought to be done. I'm talking about workstations for scientific simulations, using ...
1
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3answers
4k views

Is it possible to make redundancy on HAProxy server?

I am going to use HAProxy as a load balancer that will balance requests on 3 application servers. But what if balancer server (HAProxy) fails at some point? I was thinking of cloning the first ...
11
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4answers
494 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 ...
6
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5answers
4k views

Can you set a backup ip for your server in DNS?

Is there a way that the DNS protocol can natural hold a backup A type server address, like a backup name-server or mail server ? After googling i just got results on backup nameservers. If there isnt ...
1
vote
3answers
430 views

How to make sure that in case of our mail server being unreachable (connection down) mail still gets queued and resent once it's back up?

We have had some issues with losing internet connection once in a while. Normally that would mean our mail server is unreachable and incoming email is bouncing. We've set up MX Backup (second MX ...
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7answers
5k views

Do you lose everything when you have a hard disk failure in a multi-hard disk LVM that does NOT use RAID?

I'm debating about using LVM for a media/file server because I would like to combine multiple physical hard disks into one volume. I do not wish to use any RAID in my LVM so my question is: If one ...
4
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2answers
707 views

Is round-robin DNS a possible solution for high availability?

Let's say I have 2 IPs for a given domain (round-robin DNS). If one the IPs becomes unresponsive, will clients try to connect to the other IP? or they will just fail to establish comunication with the ...
2
votes
2answers
187 views

Two mirrored database servers, or one twice as powerful

I'm looking at setting up a seperate database server for one of my applications, the application currently runs on 3 servers; 1 frontend server and 2 application/database servers. But for performance ...
2
votes
3answers
5k views

How do you set up redundant servers?

To the sysadmins out there, I'm trying to get an idea about how you go about maintaining redundant servers for small projects. The modest number of servers in my mind is two, and three main essential ...
1
vote
2answers
376 views

SSD redundancy via HDD

Is there a way to guarantee redundancy to an SSD using an HDD? Raid 1 is the best choice to guarantee redundancy in HDDs, but SSDs are too expensive to guarantee redundancy via RAID. If I was to ...
1
vote
3answers
427 views

Distributed redundant storage solution?

Is there a way to use extra space on computers as a distributed backup system? I'm thinking that using the extra space on the systems in my network would add a lot of storage to the available pool, ...
1
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2answers
573 views

redundant network handling in linux box

I need your help very badly. I have give a solution for the requirement. I'm struggling for 5 days to get one. Requirement is to get a solution for redundant network in Linux systems. We have ...
1
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2answers
469 views

Data Backup redundancy/backups

I am looking at setting up a backup solution... well including in my backup solution actually... an external harddrive on my main file server. I then use something like Microsoft SyncToy to 'sync' ...
0
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1answer
1k views

EIGRP for Failover

Preface: Reading through O'Reilly's Network Warrior in the chapter "Ethernet Resiliency he describes the following Scenario (Trying to keep this in the limits of fair use): "Assume that the link ...