Re: High Availability.. (SQL server)

[Christian Hammers <ch@westend.com>]

Hello

Has anyone ever tried to make a webserver host with a mysql database
(used for a session database that gets updated on every click) redundant
by adding an exactly same computer and do DNS-load balancing?

If there were no SQL database this would be no problem, two web-servers
that access a shared NFS Raid for data. But you can't have two MySQL 
daemons access the same files and if you have only one SQL server for
both web servers there is no redundancy. On the other side if you have
two seperate mysql servers there is no synchronising between them, I
know about that update-log method but when serving a couple of clients
per second I doubt that the two servers syncronise fast enough to allow
using a session-db (imaging first request on A, then second request on B
but B's mysql server hasn't updated the mysql db and so the session
information are lost).

Any ideas?

bye,

 -christian-

-- 
  Research is what I'm doing when I don't know what I'm doing.
		      -- Wernher von Braun