[ale] Redundant File Servers

[Kevin O'Neill Stoll]

After some more reading it seems that the OpenGFS project
is more along the lines of what I was looking for.

Redhat seems to think the world of their port but if you
read the author's notes he spends some time pointing out
its short comings.


--- "James P. Kinney III" <jkinney at localnetsolutions.com>
wrote:

> Always renice the heartbeat to -20. Always use a serial
> line for the
> heartbeat so it has a solid interrupt. Best of all, use a
> RTOS to run
> from.
> 
> The "shoot in the head" method is good until there is a
> problem with the
> B machine. HA only work as long as there is failover
> capability.
> Headshot HA requires a fast reboot process with a good
> amount of logic
> in the HA startup. 
> 
> Note also, HA really only works best as a read-only
> service. Unless all
> nodes are active and there is a separate synch process
> from the writes.
> 
> On Tue, 2004-09-14 at 13:42, Stephan Uphoff wrote:
> > Read up on split-brain syndrome.
> > This happens when both servers think that the other one
> is dead
> > and access a shared storage device.
> > This can destroy a filesystem really, really fast.
> > Depending on your heartbeat solution this can happen as
> easily as
> > a server being to busy/low on memory,.. to send a
> heartbeat signal.
> > With a bad heartbeat solution your redundant server
> setup can 
> > be less reliable then a single server.
> > A good solution is the "shoot them in the head"
> approach:
> > If server B thinks server A is dead -> B cuts the power
> to A.
> > Now B can be sure that A is dead ;-)
> > 
> > 
> > On Tue, 2004-09-14 at 08:50, Kevin O'Neill Stoll wrote:
> > > Hi all,
> > > 
> > > I have been doing some research about either:
> > > a failover pair of fileservers, possibly
> load-balanced
> > > across the pair
> > > or
> > > a high-availability load-balanced cluster of file
> servers
> > > 
> > > I just wanted to know if anyone was already working
> with a
> > > particular setup or product that they have had
> success
> > > with. I have been doing all the basic reading /
> research
> > > that I can find via google, tldp, and linux-ha.org.
> > > 
> > > I have already found OpenGFS, a Networked Raid 1 type
> > > setup, and supposedly RedHat's cluster management
> package
> > > has a solution available.
> > > 
> > > Any thoughts would be greatly appreciated.
> > > 
> > > =====
> > > Kevin Stoll
> > > http://kevinstoll.com/
> > > 
> > > OpenSource Software...FREE!
> > > Angering Bill Gates...priceless.
> > >
>
============================================================
> > > 
> > > 
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> -- 
> James P. Kinney III          \Changing the mobile
> computing world/
> CEO & Director of Engineering \          one Linux user  
>       /
> Local Net Solutions,LLC        \           at a time.    
>      /
> 770-493-8244                   
> \.___________________________./
> http://www.localnetsolutions.com
> 
> GPG ID: 829C6CA7 James P. Kinney III (M.S. Physics)
> <jkinney at localnetsolutions.com>
> Fingerprint = 3C9E 6366 54FC A3FE BA4D 0659 6190 ADC3
> 829C 6CA7
> 

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=====
Kevin Stoll
http://kevinstoll.com/

OpenSource Software...FREE!
Angering Bill Gates...priceless.
============================================================


		
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