Disk space economy

[Shane Ambler]

On 24/07/2014 07:25, Janos Dohanics wrote:
> On Wed, 23 Jul 2014 14:40:44 -0700
> Dennis Glatting <freebsd at penx.com> wrote:
> 
>> On Wed, 2014-07-23 at 17:29 -0400, Janos Dohanics wrote:
>>> Hello List,
>>>
>>> I have a directory which contains 48 files. 35 of these files are
>>> large, close to 2 GB (reported by ls -l). 7 of the files a smaller
>>> than 4 K, the rest of the files are few dozen Ks in size.
>>>
>>> This is a FreeBSD 10 system with ZFS and RAIDZ2.
>>>
>>> du -h reports the directory to be 208G.
>>>
>>> du -A -h reports the directory to be 69G.
>>>
>>> It seems there is 2G wasted for each 1G stored data - would you
>>> explain why and what can I do make more economical use of disk
>>> space?
>>>
>>
>> Compression and/or dedup enabled?
> 
> 
> The answer is no and no:
> 
> # zfs get all data
> NAME  PROPERTY              VALUE                  SOURCE

> data  copies                3                      local

copies is the relevant setting.

>From man du -
The du utility displays the file system block usage for each file
-A  Display the apparent size instead of the disk usage

With 3 copies the disk blocks used add up to 208G but with apparent
size you get the size of each file totalling 69G - roughly 1/3