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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Redundant FreeRADIUS + MySQL

I’m working on some web service having it’s AAA implemented by FreeRADIUS + MySQL on Debian. The problem I’m working right now is HA & scalability of RADIUS. If the FreeRADIUS machine or MySQL ...
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461 views

Strategies for detecting corruption in Greyhole pools [closed]

Are there any good strategies for proactively detecting data corruption in a Greyhole pool. Suppose the following chain of events happens. c:\> copy swiss_bank_account.txt ...
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149 views

Branch Office Switch Redundancy

We're setting up a branch office with no dedicated IT person (all IT support is remote from HQ) and trying to make the infrastructure as redundant as possible. We've dealt with Internet and power, but ...
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70 views

Redundant Web Space

I have following problem. My domain is registred on service "A" My web-space (not a server) is on Godaddy. Once a week is my service unreacheble I am sure that is godaddy problem. My idea is to by ...
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Redundant Firewalls And Switches HSRP and CARP

I currently have planned 2 x uplinks (HSRP Active/Standby) 2 x pfsense firewalls (Carp Enabled) 2 x layer2 switches Please criticize or offer help on the correct way to do this. I have a feeling im ...
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1answer
201 views

VPN redundancy, failover

I am making a project for school with 3 offices wich are connected with vpn, the main server infrastructure is located in the head office and i am trying to remove all the single point of failures. ...
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2answers
184 views

SQL server redundancy without failovercluster

I would like to know what the best way is failproof your SQL Server without using a failover cluster. A failover cluster requires an enterprise server which is not an option
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1answer
280 views

Server mirroring strategy questions SQL Server replication, MySQL replication, file replication, etc

I'm working as an application developer for a company that I've been with for for some time. The business would like to mirror their existing windows server (server A) to a new server (server B) with ...
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3answers
149 views

Mirroring an entire machine

What's the most appropriate way to constantly mirror all the settings and data from one Linux machine to another? I have a critical server, which I'd like to have a "hot spare" available for in case ...
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1answer
3k views

Is Microsoft's “Storage Spaces” just LVM for Windows? [closed]

From initial reading, it looks like Microsoft's forthcoming "Storage Spaces" is an LVM-like tool for Windows. Is this a correct assessment? If it's not merely LVM-for-Windows, then what is it, and ...
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1answer
369 views

How to connect drive array to redundant motherboards?

How should one connect a small storage array, four 3TB SATA drives for now, to two motherboards or controllers as a failover system? This means avoiding adding another single point of failure such as ...
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2answers
4k views

Redundant NFS on Amazon EC2

I'm interested in building two fault tolerant/redundant NFS servers with failover at Amazon EC2. I'm familiar with tools/technologies like DRBD, Heartbeat, etc. Does Amazon provide any specific way of ...
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1answer
1k views

How to debug/fix a php/apache segmentation fault while using memcache (redundant) for session storage?

os: debian squeeze (up2date) 2 apache mod php webserver 2 memcache server i have to apache mod_php nodes which use two memcache server for redundant session storage (used variant 3 from ...
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3answers
705 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 ...
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2answers
86 views

Adding Redundancy to Win 2008 and SQL Server

We have an Amazon EC2 Windows Server 2008 with SQL Server running Email2Database and another SQL-based windows application. There is a lot of critical data on this box and we need to make sure that ...
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4answers
415 views

Providing internet redundancy for our colocation provider

My company recently had an network outage at our colocation facility that is serving our main website. The outage was caused by an upstream switch failure. I was told by my ISP (who provides us with ...
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3answers
236 views

What hardware & software consideration does a major website require to properly manage 1000+ servers? [closed]

Sorry for such a high level question. I understand the basics of server load balancing, but the concept of managing 30,000 servers is a bit foreign to me. Is it really just the same concept of ...
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2answers
165 views

Disk Redundancy across different server

I have 3 servers, all with the same specs: Intel CPU 8 GB RAM Linux or BSD Single 2TB desktop SATA with more than 10K Hours of operation, with only less than 300 GB Used My provider cannot install ...
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2answers
630 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 ...
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2answers
404 views

Overview of multiple mx server set up

Would someone please show me the overview of how multiple mx for a single domain is set up to communicate with each other? I am not talking about how to configure the postfix or DNS mx entries, I am ...
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1answer
58 views

Is the Blackberry “Move Server” command a reliable way to achieve redundancy?

BES supports moving more than one user in a domain to an alternate server as shown in the image below. Does this mean I could achieve some level of redundancy by moving users from one BES server to ...
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1answer
124 views

Cname and Amazon S3 failure

I had a quick question. If you set up a cname for your amazon bucket and lets say your main amazon s3 bucket goes down, does cname you created serve files, in other words, do your files get redirected ...
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217 views

Should redundant servers have exactly the same configuration, or slightly different?

If you provide a service on two servers to ensure high-availability, is it better to configure them in exactly the same way, of instead should you introduce slight differences to prevent "freak ...
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1answer
968 views

Redundancy for WordPress sites

For static websites I'm using HAProxy (one master, several nodes with static HTML files on them). What services in addition would you recommend to allow WordPress sites to be hosted in the same way in ...
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3answers
279 views

How to use a cloud to host web sites?

To host web sites currently we are using dedicated linux boxes hosted in the UK. But managing them is a nightmare, backups, massive loads, downtime etc... I was looking into OpenStack which was ...
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2answers
66 views

Can we route video on my redundant link while the primary is up and turn it off if the primary fails over to secondary?

We have a remote location that is currently routing data over a satellite connection. I am adding a cellular fail over if the satellite goes down. I have been asked to install video cameras that ...
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1answer
257 views

Two trunks from two switches to router

I want to connect two switches with 6 vlans to a router. Both switches are connected to other switches and are there for redundancy. Router doesn't let me put same default gateways on both interfaces ...
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1answer
80 views

Redundance for different processes running on the same server

We have a system consisting of different components/services like database, webserver, fileshare, some self programmed daemons, etc. We now have the requirement to make all components/services ...
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1answer
178 views

Amazon EC2 SQL Instance with Cheap redundancy

I'm looking at transitioning from a dedicated hosting provide to Amazon's EC2 instances. The website is an asp/asp.net website with SQL Server 2008 as it's backend. It has zero redundancy as is ...
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1answer
443 views

Redundant NFS Setup?

Is it possible to create a fault tolerant, redundant NFS server (e.g. master/slave)? Several of my web servers mount their WEBroot directories from a single NFS server (which is regularly backed up). ...
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1answer
156 views

Mac Server (Snow Leopard) NIC Redundancy on Separate Switches

I have a Mac Snow Leopard Server with 2 NIC's. Each NIC is plugged into a separate physical switch. Currently each NIC has it's own IP, but I would like to setup redundancy so that they communicate ...
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3answers
1k views

redundant nfs share

We are storing files on a network share, our application is mountig this drive using nfs. Now we have the requirement to have this drive redundant. We can add a second server and then synchronize ...
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1answer
243 views

HP P410i as online spare

Is it possible to have dual P410i SAS controllers and use one for a online spare? I am fairly new to HP servers and I will be setting up a new G7 for production use. I have been reading about HP's ...
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1answer
536 views

What is the industry standard solution for linux web server and mac file server failover systems?

I am a web developer at my company and am therefore qualified to be an IT guy, apparently. I have a single Ubuntu web and file server currently, but I want to break up the server tasks onto two ...
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4answers
454 views

MySQL Redundancy for High-Availability over the internet

I am testing out some infrastructure options before I start writing a web application. I would like to have two separate MySQL database servers at different physical locations, but if one of them ...
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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 ...
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1answer
787 views

Redundant Mailservers [duplicate]

We recently had a harddisk failure on our mail server (debian/postfix/courier) so I'm researching a way to build redundancy. The first way I found was to setup multiple mx Records in the DNS Server ...
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2answers
805 views

PowerConnect switches, Juniper firewalls and esx redundancy

Let me preface this question by saying that I am a developer and have basic knowledge of networking. My current job requires that I wear many hats. I am building out a DataCenter for our SaaS ...
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184 views

Multihomed email

Our primary MX record points to an external server which handles spam filtering, thereafter the mail is pushed to our internal mail server. The mail is never stored on the external server for longer ...
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5answers
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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 ...
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2answers
220 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 ...
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231 views

Cloning Two Windows Servers

Basically I have a server running MSSQL, MYSQL, APACHE, IIS, ORACLE, PERL and other windows services. I am looking for some hardware solution that would allow me to clone a server on to a back up and ...
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2answers
279 views

Is it possible to do storage without RAID and unnecessary redundancy?

I'm building multiple storage nodes for Riak database. Each node contains 20-40 x 2TB drives. Riak replicates each save to 3 nodes so there I have redundancy. Now the question is that what's the best ...
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4answers
2k views

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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3answers
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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 ...
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1answer
200 views

Server redundancy or failsafe for small single office server

We run a local server in our office, and have a domain name pointed to it so we can test out sites we build. We also handle some image hosting for clients for emails. Since it's a single server, if ...
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3answers
351 views

Switch Redundancy for iSCSI

I am about to implement an iSCSI solution on our network. The thing that is bothering me though is that we are only using 1 switch from the SAN to node connections. Since each node has 2 NICs, is ...
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1answer
205 views

What steps can I take to ensure that my rails app on heroku isn't effected by another ec2 outage?

My app is a victim of the recent EC2 outage and is still offline. The outage has negatively effected my business and the relationship we have with our clients. I'm hosting the app on heroku with their ...
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1answer
667 views

Effects of having a rapid ARP flush

So the scenario is we have a web server at our colocation. In front of that web server are two SonicWalls and two L2 non-stacking managed switches. We're trying to find an efficient way to set up ...
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Redundant Load Balancers for Windows-based Web Servers?

I'm having some trouble trying to figure out the technical details of the below design; specifically in the area of the redundant load-balancers. The web servers are running Windows Server 2003 R2 64 ...