Mount Point Size

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Ravikumar Wagh

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Dec 14, 2017, 5:27:52 AM12/14/17
to Ansible Project
Hello,

I was trying to get details of mout points but found that df and ansible setup module not returns same size or block count.

This is case even I specify bloc size for df command

checkout below :

ravikumar:~ # df -Th --block-size=4096
Filesystem     Type          4K-blocks    Used       Available   Use% Mounted on
devtmpfs        devtmpfs   2002838      0            2002838    0%      /dev
tmpfs              tmpfs        2005039      39          2005000    1%      /dev/shm
tmpfs              tmpfs        2005039      31067    1973972    2%       /run
tmpfs              tmpfs        2005039      0             2005039   0%        /sys/fs/cgroup
/dev/sda3       ext3          23445742    3929894 18323208  18%      /
/dev/sda1       ext3          250579        12706     224728      6%      /boot
tmpfs              tmpfs       401008         0             401008      0%      /run/user/40405
tmpfs              tmpfs       401008         4             401004      1%      /run/user/483
tmpfs              tmpfs       401008         0             401008      0%      /run/user/0

Ansible result :

        "block_available": 18323119,
        "block_size": 4096,
        "block_total": 23445742,


Can some one comment on this why they are different.

Thanks !!

Kai Stian Olstad

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Dec 14, 2017, 6:21:53 AM12/14/17
to ansible...@googlegroups.com
On 14.12.2017 11:27, Ravikumar Wagh wrote:
> I was trying to get details of mout points but found that df and
> ansible
> setup module not returns same size or block count.
>
> This is case even I specify bloc size for df command
>
> checkout below :
>
> ravikumar:~ # df -Th --block-size=4096
> Filesystem Type 4K-blocks Used Available Use%
> Mounted on
> /dev/sda3 ext3 23445742 3929894 18323208 18%
> /
>
> Ansible result :
>
> "block_available": 18323119,
> "block_size": 4096,
> "block_total": 23445742,
>
>
> Can some one comment on this why they are different.

The block_total is equal and block_available just have a difference of
89 blocks.

I doubt that the ansible fact command checking the disk have been run at
the same millisecond/nanosecond as the df command.
In a live file system a lot of IO is ongoing, like temp files been
created av deleted, so it normal that available space change all the
time.

Ansible is just running Python os.statvfs so with this command you might
be lucky to see that they are the same.

df -Th --block-size=4096 /; python -c "import os;print os.statvfs('/')"

But this oneliner with two commands is run one after the other, so it
too might be different.

--
Kai Stian Olstad

Ravikumar Wagh

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Dec 14, 2017, 6:26:59 AM12/14/17
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Thanks !!!


Got you point. 

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