BackupPC-users

Re: [BackupPC-users] How do the files look like when transferred?

2009-04-10 11:07:16
Subject: Re: [BackupPC-users] How do the files look like when transferred?
From: "Boniforti Flavio" <flavio AT piramide DOT ch>
To: "General list for user discussion, questions and support" <backuppc-users AT lists.sourceforge DOT net>
Date: Fri, 10 Apr 2009 17:02:57 +0200
[cut]

> First, in relation to your question above, appending the 
> lines to your host.pl file will override the lines above. So 
> whether you replace the existing values, or append them, you 
> get the same result. Of course, it might be less confusing to 
> comment out the original values, so that when looking at it, 
> you don't see the first definition and assume that is the 
> value in use (instead of realising the value is over-written below).

Oh, OK: didn't know that if the same parameter is being set more than
once in a "host.pl" file, only the *last* occurence will be considered.
Thanks.

> Now, back to your other thread about full backups, etc...

[cut]

> When files are deleted from the remote host, they are simply 
> "marked" as deleted in the current backup. As you would 
> expect, all the old backups still include that file, so it 
> can be restored from an older backups if needed. (Isn't that 
> one of the reasons we make backups?)

Oh, of course it is. You're right that I'm going through this BackupPC
configuration having some other commands and setups in mind. My former
goal may be confusing me too: my initial thought was to collect on one
Linux box data from remote Windows hosts, with no care about backup
"history". I just wanted to have the exact copy of that evening, nothing
more. The effective "backups" would have been taken on removable media
(tapes), to be able to have some sort of history enabling me to recover
files from a definite amount of days ago.
As BackupPC does also allow me to recover files from a few days ago (as
long as I remain in the "backup retention window"), that will be nice!

> You use various parameters such as MaxFullBackups and 
> FullPeriod etc to specify how many backups you want to keep 
> on your disk. When a backup is older than you need, it is 
> deleted and so are all the files related to that backup (only 
> if they are not needed by any more recent backups).

... so this is where "retention period" is tuned, I understand.

> Also, while you have the same files from multiple full and 
> incremental backups, they only consume 1 x the amount of 
> space. The file is stored once under the pool (or cpool) and 
> then hard links are added to make that file appear under each 
> needed backup (under the pc/<name>/<number>
> tree)

OK. So I desume that if one file gets deleted on the Windows host, it
simply doesn't get hardlinked anymore in BackupPC backup, right?
What happens if a file instead gets *changed*? Will I have 2 different
files (say the one from yesterday and the one from today)?

> Please read the FAQ/Documentation, a lot of the above is 
> explained better and in more detail there. Or, if you don't 
> want to, just trial backuppc with the default settings for a 
> while and observer how it works... It really does do a lot, 
> and does what a lot of people want. It doesn't do everything, 
> and may not do what you want, but so far, it sounds to me 
> like it does - by default....

Thanks very much for taking time to explain a bit more how BackupPC is
working.

Kind regards,
Flavio Boniforti.

------------------------------------------------------------------------------
This SF.net email is sponsored by:
High Quality Requirements in a Collaborative Environment.
Download a free trial of Rational Requirements Composer Now!
http://p.sf.net/sfu/www-ibm-com
_______________________________________________
BackupPC-users mailing list
BackupPC-users AT lists.sourceforge DOT net
List:    https://lists.sourceforge.net/lists/listinfo/backuppc-users
Wiki:    http://backuppc.wiki.sourceforge.net
Project: http://backuppc.sourceforge.net/