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Linux df command

Posted on 2014-11-28
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Last Modified: 2014-12-15
Hi Experts,
I've this Linux machine:
Linux version 2.6.18-371.3.1.el5xen (gcc version 4.1.2 20080704 (Red Hat 4.1.2-54))

I run df command:

[ora11g@hy]$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/vg_ora
                             9.7G  6.8G  2.5G  74%       /u01
/dev/lv_ora
                              59G   47G  8.2G  86%      /sxr/oracle
                                
      
I'd like to know Why the total size 9.7G isn't the same as Used+Available 6.8G + 2.5G (9.3G) and total 59G isn't the same as 47G + 8.2G (55.2)?

Thanks in advance!
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Question by:ralph_rea
6 Comments
 
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Kimputer earned 500 total points
ID: 40470362
Automatically reserved for root (during disaster, like storage fully filled, root can still log in, and do some work).
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Author Comment

by:ralph_rea
ID: 40470376
I Know that 5% of the disk might be reserved for root but with plus 5% is still less of total size 59G
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Expert Comment

by:Alexander Eßer [Alex140181]
ID: 40470400
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Expert Comment

by:omarfarid
ID: 40470468
The difference in size you observed is due to file system over head, There is no exact ratio for this as it depends on factor like number of files or dirs and their sizes.
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Expert Comment

by:arnold
ID: 40470885
Amount of space used is based on number of files and their space, inodes have a minimum file size (often 4k)such that a 1character file (1 byte)  will account for 4k of space used when computing how much space is left while not being reflected in actual space used.
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Expert Comment

by:gheist
ID: 40471926
Can you post df output without parameters?
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