Re: [BackupPC-users] Real disk space vs backuppc total size

[Les M. <le...@fu...>]

Benoit BELY wrote:
> 2007/4/30, Johan Ehnberg <jo...@eh...>:
>>
>> Benoit BELY wrote:
>> > Hi,
>> >
>> > Someone could (or try) explain to me this strange thing???
>> >
>> > I looked for disk space with unix command df :
>> >  > df -h
>> > File system          Size  Occ   Free   %Occ  Mount
>> > /dev/sda6             1,1T  135G  920G  13%    /var
>> >
>> > But when I read "BackupPC : Host Summary.
>> >
>> > 47 full backups of total size 1384.71 Go (prior to pooling and
>> compression)
>> > 72 inc backups of total size 65.73 Go (prior to pooling and 
>> compression)
>> >
>> > I don't unterstand what's happen, I must have a full device, but only
>> > 135Go seems to be occupated.
>> >

>>
>> Those numbers are before pooling and compression, which leads us to
>> these features:
>>
>> BackupPC uses compression, so if the data compresses well, you'll have
>> less on your disk.
>>
>> It also uses pooling, so if many files are identical, they will be
>> written only once on the disk, again reducing real disk usage.
>>
>> If you are unsure, try restoring and verifying the data. (You should
>> always do that in a production system anyway!)
>>

> 
> I'm surprising, the rate of compression and pool is around 10 1350 Go give
> 135 Go.
> Do you think it's normal rate???
> I heard it should be around 5 or 6 but 10 seems to be large rate for me.

10 isn't unreasonable.  The factors that can make it higher are files 
that are very compressible like text files or database files with a lot 
of blank records, and duplicate files, both from the same files on 
multiple machines and from having multiple full runs of the same machine 
in the archive.

-- 
   Les Mikesell
     les...@gm...