Messages in this thread | | | Date | Fri, 22 Nov 2002 20:19:14 +0100 | From | Gunther Mayer <> | Subject | Re: Failover in NFS |
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Jesse Pollard wrote:
>On Thursday 21 November 2002 02:58 pm, Bill Davidsen wrote: > > >>On Mon, 18 Nov 2002, Jesse Pollard wrote: >> >> >>>It would actually be better to use two floating IP numbers. That way >>>during normal operation, both servers would be functioning simultaneously >>>(based on the shared storage on two nodes). >>> >>>Then during failover, the floating IP of the failed node is activated on >>>the remaining node (total of 3 IP numbers now, one real, two floating). >>>The NFS recovery cycle should then cause the clients to remount the >>>filesystem from the backup server. >>> >>>When the failed node is recovered, the active server should then disable >>>the floating IP associated with the recovered server, causing only the >>>mounts using that IP number to fall back to the proper node, balancing >>>the load again. >>> >>> >>That works for stateless connections, but for stateful connections like >>POP, NNTP, SMTP, etc, you will lose all the connections currently >>actively. >> >> > >yes. That is the point. NFS v3/4 CAN use TCP connections. The only way >I know to force them back to the recovered server IS to kill the connection. > NFS over TCP does work very well for such failover configurations with a virtual IP address.
To the NFS client a failover is indistinguishable from a server crash+reboot which is guaranteed to work by NFS standard definition.
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