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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696 views

Redundancy scenarios for a small network centered around a Cisco 3560X switch

As the title says, I manage a small network which uses a Cisco 3560X as the core switch. We have recently got a 2nd identical switch and I have started thinking about how to add some redundancy to the ...
2
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2answers
296 views

A and PTR records and redundant Internet connections

Want to set up PTR record(s) to handle the following: Site with mail server (Exchange 2010) has three Internet connections, with the firewall handling load balancing. I know that if the Internet ...
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1answer
351 views

How to setup cluster of virtual machines to host web application with fail-over redundancy?

I would like to know how to setup a cluster of virtual machines to host a web application. We are expecting a high volume of clients connecting. I would like a cluster of virtual machines (or ...
3
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4answers
165 views

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. ...
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1answer
444 views

Networking: Does slavedisk0 take over for disk0 in the event of a fault?

My bootvar is set to boot up images from disk0. The 6500 series switch has two redundant supervisors. Each supervisor has a PCMCIA card with the exact same IOS images in the 0 slot. The secondary ...
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1answer
269 views

How to setup a failover solution for Windows 2003 SMTP Server?

I'm currently running Windows SMTP Server on a rented Windows 2003 Server VM. There are times when my hosting company network is down and my clients can't send their emails via the SMTP Server host I ...
44
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7answers
6k 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 ...
3
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1answer
1k views

Configure fallback redis server

I am using redis as a cache server. Can I somehow configure multiple redis servers, that the cache is fully functional (read/write) even if some of them go offline? I looked into master->slave, but ...
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2answers
940 views

Record DNS for 2 static ip - fault tolerance

i've a web server in a DMZ reachable from 2 different public static ip addresses provided by 2 different internet connection by 2 different ISPs. I want to create a record let's say ...
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1answer
70 views

Preparing a server for mysql replication and use it as standalone

I want to host an application on a single server running MySQL server. To get the best performance I plan on using a UNIX socket connection (to avoid TCP overhead). Later, I would like to scale up by ...
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2answers
96 views

Domain name to point to 2 different servers

I'm looking to setup cheap redundancy for a website, such that I signup with 2 separate shared hosting accounts. The likelihood of both being down at the same time would be small. Is there a way to ...
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2answers
386 views

Basic redundancy for EC2 (wordpress + mysql)

I've got a website that I would like to add redundancy to. It's not a massive website, and will probably only receive a handful of database updates and/or files per day, however it's very important ...
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2answers
121 views

High available and secure FrontEnd to WebApps behind a firewall [closed]

my question is about proposed implementation of high available and secure FrontEnd to WebApps behind a firewall. The components of the network and their relationships are as follows: 1) 2 WebApps ...
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1answer
102 views

ISP Redundancy Hardware

I've tested Microsoft TMG 2010 to load balance my two DSL lines and it works fine. Can I expect the same level of results and security to be achieved with a less expensive firewall appliance?
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1answer
452 views

Email server - redundant, mobile, and secure [duplicate]

Possible Duplicate: 100% uptime for a web application I wish to create my own personal email server. I can't have any downtime - so I have 3 machines at different IP adresses around the ...
1
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2answers
207 views

Servers configuration to improve performance and offer redundancy for ASP.NET site with SQL Server

I'm administrating a fairly large website (currently about 300 thousand page views a day) which is expected to grow fast. Currently both IIS and SQL Server are running in a quad core server, with RAID ...
2
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1answer
170 views

Configure a backup Win 2008 R2 Server

Scenario is a small network with a Server 2008 R2 running AD, DHCP, DNS, Print & File Sharing. We'd like to build a backup server to continue operations uninterrupted should the main server go ...
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1answer
392 views

Sonicwall firewalls and redundancy of route based vpns

I am attempting to configure a route based vpn on a Sonicwall TZ device. The datacenter has two public IPs on different subnets (A and B). The remote office has 1 public ip (C). When I configure ...
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3answers
635 views

Redundant Linux Servers in Seperate Datacenters

I have 2 CentOS linux servers in separate data centers on each site of the country. These linux machines run a small web sites on Apache with a MySQL backend. There currently is no VPN connectivity ...
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1answer
223 views

How to use Route53, or any other service, to redirect to a “backup” site when the main one is unreachable

I have example.com managed by a DNS server that associates it to some IP address (ip1), owned by a first web server where the full site is hosted. I also have a secondary webserver (with ip2) that ...
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2answers
238 views

Is ntp.ubuntu.com redundant?

Does anybody know if Ubuntu's NTP servers are redundant? If I dig them, I get: ;; ANSWER SECTION: ntp.ubuntu.com. 280 IN A 91.189.94.4 vs. when I dig pool.ntp.org: ;; ANSWER SECTION: ...
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2answers
3k views

Adding redundancy to Hyper-V without a SAN

My organization has two identical servers, HP ProLiant DL380 G5. We do not have a SAN device. Each server has 8x 146GB HDD, and 48GB RAM. One server is currently configured as an Exchange server. ...
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1answer
67 views

Redundant Connection Issue

I'm trying to set up a redundant connection for our web hosting servers. I have a BGP-capable router connecting two lines from two separate ISP's, one fiber (primary), one DSL (failover). I've already ...
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2answers
2k views

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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2answers
394 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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1answer
127 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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3answers
69 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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0answers
1k views

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
154 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
159 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
258 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 ...
2
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3answers
146 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 ...
4
votes
1answer
2k 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
295 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 ...
4
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2answers
3k 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 ...
1
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1answer
814 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 ...
3
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2answers
445 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
73 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 ...
0
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4answers
373 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 ...
4
votes
3answers
226 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 ...
2
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2answers
143 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 ...
2
votes
2answers
479 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
311 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
55 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
119 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 ...
4
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3answers
209 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 ...
2
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1answer
762 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
276 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
233 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 ...