[Nut-upsuser] ordered shutdown

[Arjen de Korte]

Citeren Charles Lepple <clepple op gmail.com>:

>> Our network system is quite complex and we need shutdown sequence  
>> levels. The servers depend on each other because of NFS and SQL  
>> connections and the like.
> There is a bit of sequencing in the master/slave protocol, but I have
> not had the time to set something up to try your particular situation.

Basically, this needs to be dealt with in the client application.  
Since we don't provide Windows clients (which Lars apparently is  
using), I have no idea if this is possible with those. Using the  
'upsmon' client (but this requires some sort of *NIX system) this is a  
trivial however, by staging the FINALDELAY time we have in  
'upsmon.conf'.

Assuming there are clients connected to the SQL servers which in turn  
require NFS service you would use something like the following

     FINALDELAY 0 (for the clients)
     FINALDELAY X (for the SQL servers)
     FINALDELAY X+Y (for the NFS servers)

The values of X and Y depend on how long the clients need for  
finishing their business with the SQL servers (X) and how long the SQL  
servers needs for doing their thing on the NFS servers (Y).

You'll want a sufficient 'ups.delay.shutdown' period to make sure that  
all systems have not only started their shutdown sequences, but have  
also finished them before the power is actually cut. The use of  
FINALDELAY in the above only sequences the start of the shutdown, so  
it doesn't know when the systems are actually switched off. This is by  
design, since you don't want to stall shutting down if one system is  
unresponsive or takes longer to shutdown than expected (which would  
put all remaining systems at risk for a hard shutdown).

Best regards, Arjen
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