[ VMWare ESX just allows me to setup many virtual machines on one hardware ]
In theory, from reading the documentation in my limited experience, it allows
the clustering of many real hardware elements to support a Virtual
Datacenter/Virtual Infrastructure.
In practice, 1 of 6 in a VMware cluster had a memory problem; we vmotioned the
DSpace to another in the cluster, there was no break in service, the real host
went off-line for servicing. The same was done for upgrading bios. The vmotion
can be set to trigger conditionally. It gives you one more layer for high
availability.
You can use linuxha or similar for high availability.
-- Van Ly
________________________________
From: John Preston [mailto:byhisde...@gmail.com]
Sent: Tue 4/21/2009 12:39 AM
To: Van Ly; dspace-tech@lists.sourceforge.net
Subject: Re: [Dspace-tech] High Availability DSpace
There is also VMware ESX with vmotion of virtual host in case of
underlying real host having troubles. You can arrange it with LVS, linuxha, etc
anyway you like
The VMWare ESX just allows me to setup many virtual machines on one hardware,
but I would still need to handle the issues related to keeping multiple DSpace
instances in sync.
John
-- Van Ly
________________________________
From: Robin Taylor [mailto:robin.tay...@ed.ac.uk]
Sent: Mon 4/20/2009 6:25 PM
To: John Preston; dspace-tech@lists.sourceforge.net
Subject: Re: [Dspace-tech] High Availability DSpace
Hi John,
I am a little out of my depth here so forgive me if I am taking
rubbish, but I am not sure that having two servers constantly available is the
right solution for you. Typically this setup would be used to spread the load
if the application is in high demand. To provide high availability in the event
of failure you would typically use some clustering software which will failover
of IP addresses etc from the failed machine to another machine which sits idle
ready to be used in the event of a failover. I just did a quick google on
'Centos clustering' and this came up
http://www.linuxtopia.org/online_books/centos_linux_guides/centos_cluster_configuration_and_management/.
I don't know if its free or if there are any free alternatives.
Cheers, Robin.
Robin Taylor
Main Library
University of Edinburgh
Tel. 0131 6515208
> -----Original Message-----
> From: John Preston [mailto:byhisde...@gmail.com]
> Sent: 20 April 2009 00:16
> To: dspace-tech@lists.sourceforge.net
> Subject: [Dspace-tech] High Availability DSpace
>
> I have to set up a DSpace instance and want to make it highly
> avalable. Its not that the load is gonna be that heavy to
> start with, but I want to have some redundancy such that if a
> machine goes bad, the system will still function while I look
> about changing it out. So I'm planning on using LVS on Centos.
>
> I will have two routers which will keep traffic going to two
> webservers on the backend which have duplicate DSpace
> instances. Now to have duplicate instances I will use a
> common NFS store for the assest store, but for the database I
> will point each of the DSpace instances to a common database
> on the network. I know this will be a single point of
> failure, but I can either restore the database quickly if I
> need, or I can get synchronisation across postgres databases
> dynamically if I want (slony, etc).
>
> My question is: can anyone give me a simpler or better way to
> achieve high availability, and is DSpace code able to manage
> different web applications writing to the database across
> different instances.
>
> John
>
>
>
>
--
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.
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