Op 3-11-2010 12:16, Stan Hoeppner schreef:
Johan Hendriks put forth on 11/3/2010 3:32 AM:
Hello, i am working primarly with FreeBSD, and the latest release has a service called HAST. See it as a mirrored disk over the network. You can install both machines with dovecot, and use the hast disk as the data storage. With CARP in the mix, when the master machine fails, it starts dovecot on the slave. This way you have a failover without user interference.
How do you automatically redirect clients to the IP address of the slave when the master goes down? Is this seamless? What is the duration of "server down" seen by clients? Seconds, minutes?
When you bring the master back up after repairing the cause of the failure, does it automatically and correctly resume mirroring of the HAST device so it obtains the new emails that were saved to the slave while it was offline? How do you then put the master back into service and make the slave offline again?
The servers work with an virtual ip. Carp does this, i use it for the firewalls on our location. Server 1 has ip adres 192.168.1.1, server 2 gets 192.168.1.2, and the virtual addres is 192.168.1.3 The clients connect to the virtual address 192.168.1.3, and contact the machine wich is master at that moment.
I do not know how the rebuild goes with hast, if the master provider goes down, like i said, i need to try and test it. Maybe an question on the freebsd-fs mailing list will answer this.
More about HAST http://wiki.freebsd.org/HAST More about Carp http://www.freebsd.org/doc/nl/books/handbook/carp.html
regards, Johan Hendriks