[ale] Redundant File Servers

[James P. Kinney III]

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.
> > ============================================================
> > 
> > 
> > 
> > _______________________________
> > Do you Yahoo!?
> > Declare Yourself - Register online to vote today!
> > http://vote.yahoo.com
> > _______________________________________________
> > Ale mailing list
> > Ale at ale.org
> > http://www.ale.org/mailman/listinfo/ale
> > 
> > 
> 
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> http://www.ale.org/mailman/listinfo/ale
> 
> !DSPAM:41472db2172307804616587!
-- 
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
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part