Re: [BackupPC-users] How BackupPC determines which host should make the next backup

[Matthias M. <mat...@gm...>]

Chris Robertson wrote:

> Les Mikesell wrote:
>> Matthias Meyer wrote:
>>   
>>> Assumed I have 10 hosts and the maximum number of simultaneous backups
>>> to run is 5.
>>> Further assumed all 10 hosts have to make a backup today.
>>> 4 of them have theire last backup made 2 days ago and 3 of them
>>> yesterday. 2 have a partial backup and 1 have no backup.
>>> 9 hosts are reachable (ping) the last times but 1 host not. Therefore
>>> the BlackoutPeriods for 9 hosts can be applied by backuppc and for 1
>>> host not. Nevertheless the time now is not within this blackout period.
>>>
>>> Which 5 hosts will request theire backups?
>>>
>>> Will BackupPC try the hosts in alphabetical order?
>>> Or will BackupPC use informations about the oldest backup and try this
>>> hosts at first?
>>>     
>>
>> The first cut will be which ones have reached their backup interval
>> (since the last backup) at each wakeup time.  That is, at each wakeup it
>> will consider only the set that is not within a blackout and has passed
>> the interval time since it's last run - and these will not start if the
>> ping test fails.  I'm not sure who wins if there are more choices at one
>> time than your concurrency limit allows - it might just be the order in
>> the host list.  I just start one early from the web interface if I want
>> to push it ahead.
>>   
> 
>  From the source (/usr/local/BackupPC/bin/BackupPC on my machine)...
> 
> #
> # Compare function for host sort.  Hosts with errors go first,
> # sorted with the oldest errors first.  The remaining hosts
> # are sorted so that those with the oldest backups go first.
> #
> sub HostSortCompare
> {
>     #
>     # Hosts with errors go before hosts without errors
>     #
>     return -1 if ( $Status{$a}{error} ne "" && $Status{$b}{error} eq "" );
> 
>     #
>     # Hosts with no errors go after hosts with errors
>     #
> 
>     return  1 if ( $Status{$a}{error} eq "" && $Status{$b}{error} ne "" );
> 
>     #
>     # hosts with the older last good backups sort earlier
>     #
>     my $r = $Status{$a}{lastGoodBackupTime} <=>
> $Status{$b}{lastGoodBackupTime};
>     return $r if ( $r );
> 
>     #
>     # Finally, just sort based on host name
>     #
>     return $a cmp $b;
> }
> 
> Chris
> 
:-)
Thanks for the realy fast response
br
Matthias
-- 
Don't Panic