Re: hot spare / log shipping work on

Gaetano Mendola wrote:

>
>         a1) If exist check that is a 16MB file ( the request can
> ~                arrive during the copy ),

I think this will fail under windows: "copy" first sets the file size 
and then transfers the data. I wouldn't rule out that some Unices use 
the same implementation.

>
> ~            a2) If the file not exist this mean that is not yet 
> recycled and
> ~                is a partial file present on the partial directory,
> ~                check if the "alive" file is older then 2 minutes.
> ~                   a21) If the file is older than 2 minutes I assume 
> that
> ~                        the master is dead:

I'd concentrate on cold failover: the user (or the OS) must call a 
script to cause a fail-over. The tricky thing are the various partial 
connection losses between master and spare: perhaps the alive file is 
not updated anymore due to a net split, but the master is still alive. 
Unless you are really careful both master and spare could run.

I think SAP DB / MaxDB supports failover - perhaps it would be 
interesting to check their failover scripts.

--   Manfred