Browsing articles tagged with "highavailability - Admins Goodies"
Jan 13, 2013
tom

Should HA hardware be in separate cabinets?

I want to host (co-located) a service at a Pier1, Q9 or some similar hosting facility. Is it best practice to put my failover hardware in separate cabinets, and in your experience, will the hosting provider allow this? My concern is that if something happens, say catches fire in the cabinet or a disgruntled rack renter pours his coke into the servers, both my HA stacks will be compromised. In your experience, if I put […]

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Dec 10, 2012
tom

HAProxy MySQL Failover is not starting

I am trying to setup HAProxy with MySQL failover with Ubuntu. I used a setup similar to this serverfault question, however I am getting the following error when starting haproxy: [ALERT] 341/220001 (17405) : parsing [/etc/haproxy/haproxy.cfg:29] : unknown option ‘mysql-check’. [ALERT] 341/220001 (17405) : Error(s) found in configuration file : /etc/haproxy/haproxy.cfg [ALERT] 341/220001 (17405) : Fatal errors found in configuration. I even tried installing the lastest version of HAProxy (1.4.22). Does anyone know how to […]

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Nov 26, 2012
tom

How to configure HA iSCSI for Solaris 10

BACKGROUND: We have a StarWind NAS that we are currently using for High Availability storage with our Windows network. Starwind has mirrored drives and multiple ip paths, that the Windows Server combines into one HA disk store. QUESTION: How do I accomplish the same thing under Solaris 10? I’ve looked at ZFS but to document seems to indicate that ZFS wants to do its own raid/mirroring. I can also attach via iSCSI from Solaris and […]

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Nov 7, 2012
tom

Is this a solid (and cheap) High Availability idea for my website and database if the zombi’s attack?

I have an Idea for fail-over high availability for my website but i am not sure if this is good, bad or a disaster in itself. My main server hosts an ASP.net website that uses a SQL server database on another server. Both servers are running mirrored raid drives, two network cards, 2 switches etc. The provider is guaranteeing 99.999% up time but something did go wrong and they took almost a a day before […]

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Oct 3, 2012
tom

Cheapest High Available Web Server [closed]

I would like to create a high-available setup (e.g. a small cluster) for a webserver, i.e. it will run Apache, PHP and MySQL. There will be between 2-8 small websites running with only very little traffic and workload. High availability is however very important. I don’t want to be dependent on 1 datacenter, so there must be a minimum of 2 servers placed in different datacenters, and if one server goes down, the user must […]

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Sep 29, 2012
tom

Should an HA failover occur in this scenario?

I’m running vSphere 5 in an HA cluster across two hosts (vsphereA and vsphereB). I have the HA cluster configured for host monitoring and datastore heartbeat monitoring with admission control disabled (hopefully I rightfully understand that datastore heartbeat monitoring prevents inadvertent and unwanted HA failovers due to management network isolation). Each host has a single connection to a dedicated iSCSI network and iSCSI target (no MPIO). All vmdk’s for all VM’s exist on the iSCSI […]

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Sep 25, 2012
tom

How to handle server failure in an n-tier architecture?

Imagine I have an n-tier architecture in an auto-scaled cloud environment with say: a load balancer in a failover pair reverse proxy tier web app tier db tier Each tier needs to connect to the instances in the tier below. What are the standard ways of connecting tiers to make them resilient to failure of nodes in each tier? i.e. how does each tier get the IP addresses of each node in the tier below? […]

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Aug 19, 2012
tom

Risks of Network Partitioning When a Split Brain Creates a Security Flaw

I’m looking to create a high-availability, scalable networking solution by using a distributed system of data. A node here, describes a network that has control over one copy of the data. These nodes might contain more than one machine but has one copy of the data. The nodes will contain data records which can be in a spent state or an unspent state. A client can request a transition for a record to go from […]

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Jul 6, 2012
tom

IP failover on different subnets

I have two real servers, on different subnets, each one with a permanent IP, and with a failover IP that can be used by either server. The hoster provides an API with which I can assign the failover IP to any of the servers. So I need to run a daemon on each of the servers, which will be monitoring the health of the local server, and at the same time communicate with its counterpart […]

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May 22, 2012
tom

Windows 2008 ignores Gratuitous ARP requests

We recently saw an issue after a fail over of our router where our Windows 2008 Boxes didn’t start talking to the primary router after fail-back. When we did some digging they still had the ARP entry from the secondary router. According to the TechNet Blog this is by-design: First, a Windows Vista or Windows Server 2008 will not update the Neighbor cache if an ARP broadcast is received unless it is part of a […]

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