A computer cluster consists of a set of loosely connected computers that work together so that in many respects they can be viewed as a single system.

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22
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How can I pre-sign puppet certificates?

Puppet requires certificates between the client (puppet) being managed and the server (puppetmaster). You can run manually on the client and then go onto the server to sign the certificate, but how do ...
18
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6answers
5k views

Bidirectional real-time sync of large file tree between two distant linux servers

By large file tree I mean about 200k files, and growing all the time. A relatively small number of files are being changed in any given hour though. By bidirectional I mean that changes may occur on ...
17
votes
1answer
6k views

Which messaging layer to use, Heartbeat or Corosync?

Just about finished my research into setting up a web server cluster and I'm still undecided as to which messaging layer to use with Pacemaker. The servers I'm using are all Fedora so both layers are ...
14
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7answers
2k views

When is the right time to introduce high availability for web site?

When is the right time to introduce high availability for web site? There are many articles on High Availability options. It’s not that obvious however WHEN is the right time to switch from single ...
14
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4answers
4k views

Managing an application across multiple servers, or PXE vs cfEngine/Chef/Puppet

We have an application that is running on a few (5 or so and will grow) boxes. The hardware is identical in all the machines, and ideally the software would be as well. I have been managing them by ...
10
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5answers
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what cluster management software to use for linux?

I have found the following cluster management software tools: pacemaker (clusterlabs.org), - original a Heartbeat project, focus for high-availability, will be in the next debian version openqrm ...
9
votes
4answers
2k views

DIY Hadoop Cluster - Heat & Dust issues?

Following are links of my DIY 6-Node Hadoop Cluster using i3 Machines, What is the best possible way to protect my design from dust & provide better heat transfer? What should I use to cover ...
9
votes
4answers
2k views

Advantages of Using Nginx or HA Proxy as Load Balancer

In our environment we us both Nginx and HA Proxy on different clusters. Are there advantages of using one over the other? Or, what is the best way to go about load balancing a basic LAMP server ...
8
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3answers
15k views

nginx automatic failover load balancing

I'm using nginx and NginxHttpUpstreamModule for loadbalancing. My config is very simple: upstream lb { server 127.0.0.1:8081; server 127.0.0.1:8082; } server { listen 89; ...
8
votes
2answers
210 views

A roundrobin for incoming files

A bunch of new files with unique filenames regularly "appears"1 on one server. (Like hundreds GBs of new data daily, solution should be scalable to terabytes. Each file is several megabytes large, up ...
8
votes
6answers
5k views

Best way to load balance across multiple static file servers for even an bandwidth distribution?

First off, I'll explain my situation to you. I'm running a fairly popular website as a side project, so I can't really invest a ton of money into it. I currently have just one server with HAProxy in ...
8
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4answers
140 views

Test-Cluster Powershell cmdlet List vs Validate

The Powershell cmdlet Test-Cluster queries a myriad of data and performs validation tests which it wraps into a pretty report. If you run Test-Cluster -List you get a list of item's you can ...
7
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4answers
4k views

Ganeti vs Proxmox [closed]

I'm system administrator in small software house. I'm going to virtualise our servers. The main reason for doing this is providing highest possible uptime, but probably it will also increase resources ...
7
votes
11answers
819 views

Which database servers are not interrupted by server reboots? (Clusters?)

We have been asked to deliver a system where the central database server continues its operations, even when applying security updates to the server's operating system or to the database server ...
7
votes
2answers
2k views

Make a Docker application write to stdout

I'm deploying a 3rd-party application in compliance with the 12 factor advisory, and one of the points tell that application logs should be printed to stdout/stderr: then clustering software can ...
7
votes
5answers
3k views

Load balancing and HTTPS strategies

I am faced with the following problem: Servers get saturated since current load balancing strategy is based on client IP. Some corporate clients access our servers from behind large proxies so all ...
7
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2answers
147 views

What “pieces” are needed in order to set up a cluster of physical servers?

Background: Currently, we use Rackspace cloud servers. We have no intention to stop using them, but would like to look into setting up a cluster of physical servers (probably desktop computers in the ...
7
votes
1answer
274 views

Heartbeat meatware STONITH on kernel panic

I have a two node cluster with heartbeat and DRBD managing a mysql resource. The failover works great if I halt the primary, reboot it, or disconnect the network connection. However, if the primary ...
6
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7answers
473 views

High availability virtual machines

I've been reading a lot about high availability virtualization, either via Hyper-V or VMWare. In that context, essentially high availability means that the VM is hosted by a cluster of physical ...
6
votes
2answers
758 views

How do Active Directory domain joined computers (native MS Windows or Linux with winbind) determine the closest password server?

How do Active Directory domain joined computers (native MS Windows or Linux with winbind) determine the closest password server? This question implies a cluster with 2+ Active Directory servers in ...
6
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2answers
3k views

SSH Host key verification issues using VIP

We have 2 production servers on a VIP, only one is in use at a time, for example: myservice.mycompany.uk normally points to server1, in the event that server1 fails it is changes to point at server2. ...
6
votes
9answers
622 views

Is it possible to create a faster computer from many computers?

My post below was (I think rather unfairly) closed on StackOverflow hence my reposting here. Original Question: How can I use several computers to create a faster environment? I have about 12 ...
6
votes
3answers
344 views

Is Clustering really = High Availability?

These days clustering is becoming synonymous to high availability. As an enterprise architect I have to shake my head in disbelief. IMHO, clustering can be a component of HA but is far from being HA ...
6
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3answers
192 views

Disaster Recovery Planning, tower or rack?

I'm working on this project to develop a system with centralized information regarding emergencies delivered via open Wi-Fi on a small city. I'm from Chile, so we thought of this system to work ...
6
votes
7answers
1k views

How can I shut down (power off) cluster nodes during low load?

I'm developing software for the energy consulting business and in monitoring energy use in datacenters, I've noticed that the typical electric load "pattern" of a datacenter is just a flat line, ...
6
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3answers
2k views

Maintenance plan for SQL Server Database Mirroring

We're using SQL Server database mirroring and we're trying to create a db maintenance plan to backup the database. The problem is that when the server is not the primary database the plan fails. I was ...
6
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6answers
6k views

Cluster failover and strange gratuitous arp behavior

I am experiencing a strange Windows 2008R2 cluster related issue that is bothering me. I feel that I have come close as to what the issue is, but still don't fully understand what is happening. I ...
6
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5answers
2k views

Hyper-V Cluster with failover - NETWORKING

We are looking to setup a 3 node Hyper-V cluster with live migration and failover using: 3 x Dell R710's with dual quad core Xeon & 128 GB RAM & 6 NICs in each 1 x Dell MD 3220i SAN We ...
6
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3answers
6k views

Are ZFS clustered filesystems possible?

Is it possible to create a ZFS cluster? Or would you need to go the seemingly ugly (to me at least) route of ZFS with UFS formatted pools governed by GlusterFS? The idea is to see if it is possible ...
6
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3answers
3k views

VMware Virtual Machine Clustered Filesystem Setup

The situation is: I am running VMware ESX 3.5 (3 ESX Hosts w/ vCenter Server in a Cluster); I need five Virtual Machines to read from the same disk running a clustered file system; I cannot ...
5
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5answers
481 views

Usage ideas for a cluster at a university

I currently am a student worker at a medium sized university. i work for the college of science (includes math, stat, comp sci, physics, chem, and biology) and as a "technician"; which basically is a ...
5
votes
3answers
1k views

Upgrading ubuntu release on a cluster of servers

I have a cluster of about 50 ubuntu nodes which are currently running maverick release. I'd like to upgrade them to oneiric, but I'm having a difficulty choosing the right tools. I know ubuntu has ...
5
votes
5answers
2k views

Clustering F5 Big-IP Devices; Is it Possible?

I developed a web application. It will run on a farm of five IIS servers. It's absolutely essential that once a session is established with a server in the farm, further HTTP requests within that ...
5
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6answers
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(*nix) Cloud/cluster solutions for scalable web-services

I'm going to build a high-performance web service. It should use a database (or any other storage system), some processing language (either scripting or not), and a web-server daemon. The system ...
5
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3answers
508 views

What is your provisioning method? (out of the cardboard -> bare metal -> fully functional server)?

Trying to cut down our deploy times and looking for suggestions and shortcuts you or your team uses to get back in the terminal and out of the data center. Looking at the entire process from ordering ...
5
votes
4answers
517 views

MySQL Clustering

I run a mysql server that hosts around 50Gb of data (primarily for around 250 websites), and am wondering what my options are for setting up a redundant MySQL cluster? The primary purpose would be ...
5
votes
8answers
2k views

Linux stretch cluster: MD replication, DRBD or Veritas?

For the moment there's a lot of choices for setting up a Linux cluster. For cluster manager: you can use Red Hat Cluster manager, Pacemaker or Veritas Cluster Server. The first one has the most ...
5
votes
1answer
805 views

Linux Filesystem options for iSCSI shared storage

I am trying to determine my 'best choice' for a filesystem to use for a shared storage device that will be mounted via iSCSI across an indeterminate number of servers. Setup: 27TB Synology RS2212+ ...
5
votes
1answer
3k views

mount.ocfs2: Transport endpoint is not connected while mounting…?

I have replaced a dead node that was running in dual-primary mode with OCFS2. All the steps work: /proc/drbd version: 8.3.13 (api:88/proto:86-96) GIT-hash: 83ca112086600faacab2f157bc5a9324f7bd7f77 ...
5
votes
3answers
1k views

What to use for software-based shared file storage?

The situation: setting up a load balancer Currently we have all of our servers (running CentOS Linux) in pairs in our data center: each server has a mirroring server. We don't employ any load ...
5
votes
3answers
852 views

Need suggestions for a R/W distributed file system for a webserver cluster running Apache+PHP

In the last few months, I've been trying to find the best way to share the content of multiple websites across multiple web servers (12+) all running Apache+PHP. One of the biggest challenge I face is ...
5
votes
3answers
2k views

High Availability for SSL Web Site

One of our web server clusters serves a moderate number of busy e-commerce applications. At present, each site lives on a specific web server and has a hot-spare copy mirrored to another web server ...
5
votes
8answers
1k views

Is iSCSI SAN still a spof in a cluster? Can it be highly available?

I'm currently evaluating a Win2k8 two node file server cluster that is connected to a Win2k8 Storage Server iSCSI SAN. The failover is working perfectly, but I'm now wondering what will happen if the ...
5
votes
3answers
537 views

SQL Server clustering options

Can anyone give an high-level overview of the options available for SQL Server clustering, their pros and cons? Is it better to use Microsoft Clustering services or SQL Server native clustering? Does ...
5
votes
2answers
1k views

csync2 ERROR: Connection to remote host failed

I was unable to find any articles to answer this question, so my best bet was to post this here: Scenario We have 2x application servers in production hosting a PHP website and I would like some ...
5
votes
4answers
6k views

How to script printer creation on a Windows Server 2008 R2 clustered print server?

As per subject. I've found some ways of scripting printer creation on Windows print servers using WMI, but it looks like WMI doesn't support clustered print servers (or clustered servers at all). ...
5
votes
1answer
377 views

Windows Server Cluster & Strange Day Light Savings Time Behaviour

Over the weekend (Sunday March 27th) Daylight Savings Time kicked in here in Ireland and so all the servers (all win2k3 server) in our Production Environment updated their Times +1 Hour. However ...
4
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4answers
3k views

Load balanced Drupal servers: a good way to share data among the servers?

I'm trying to get an overview of how i would go about creating a load balanced web server setup. Setting up the actual load balancer and adding two or more web servers seems fair enough. However, I ...
4
votes
5answers
124 views

send files to dozens of servers quickly

We have a cluster of machines (around 50 and growing). Each machine has a search index that needs to be updated multiple times per day. We currently update the index on each machine individually, but ...
4
votes
5answers
1k views

Decent 1gb switch (16-24 port) for rack

For a rack containing a smaller nubmer of servers (5 at the moment, going to stay in this area), I am looking to replace the currently aging 100Mbit switch with a 1Gb switch. This is for the backend ...