[ale] Redundant File Servers

[Bob Toxen]

On Tue, Sep 14, 2004 at 01:42:34PM -0400, 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.
Yup!

> 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.
Yup!

> 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 ;-)
Yes, that's how we do it.  We cut power via an external device
of our own proprietary design (done by hardware genius and ALEr,
Mike Panetta).

Our initial one is a 240V unit for Europe.

Best regards,

Bob Toxen, CTO
Fly-By-Day Consulting, Inc.
"Your expert in Firewalls, Virus and Spam Filters, VPNs,
Network Monitoring, and Network Security consulting"
http://www.verysecurelinux.com       [Network & Linux/Unix Security Consulting]
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> 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.
> > ============================================================