What information is known about the files?
meta-data
- A file system relies on data structures described the files and not just the content of the files
- meta-data: data that describes data or the relationship between data
- Each file is associated with an
inode- integer number related to the meta-data
- inodes store information such as
- ownership
- access mode (read, write, execute permissions)
- file type (text, binary, data, compiled program)
- inode number can be found with
ls -icommand.- add the inode to the first column
Example
$ mkdir test
$ cd test
$ touch bob
$ ln bob robert
$ ln -s bob bobby
$ ls -li
total 44
144170437511753087 -rw------- 2 beckbw G-814141 0 Jun 6 07:07 bob
144170437511753088 lrwxrwxrwx 1 beckbw G-814141 3 Jun 6 07:07 bobby -> bob
144170437511753087 -rw------- 2 beckbw G-814141 0 Jun 6 07:07 robert
$ stat bob robert bobby
$ stat *ob*
File: `bob'
Size: 0 Blocks: 0 IO Block: 4194304 regular empty file
Device: dab3078h/229322872d Inode: 144170437511753087 Links: 2
Access: (0600/-rw-------) Uid: (827624/ beckbw) Gid: (814141/G-814141)
Access: 2017-06-06 07:07:31.000000000 -0500
Modify: 2017-06-06 07:07:31.000000000 -0500
Change: 2017-06-06 07:07:40.000000000 -0500
Birth: -
File: `bobby' -> `bob'
Size: 3 Blocks: 0 IO Block: 4096 symbolic link
Device: dab3078h/229322872d Inode: 144170437511753088 Links: 1
Access: (0777/lrwxrwxrwx) Uid: (827624/ beckbw) Gid: (814141/G-814141)
Access: 2017-06-06 07:07:46.000000000 -0500
Modify: 2017-06-06 07:07:46.000000000 -0500
Change: 2017-06-06 07:07:46.000000000 -0500
Birth: -
File: `robert'
Size: 0 Blocks: 0 IO Block: 4194304 regular empty file
Device: dab3078h/229322872d Inode: 144170437511753087 Links: 2
Access: (0600/-rw-------) Uid: (827624/ beckbw) Gid: (814141/G-814141)
Access: 2017-06-06 07:07:31.000000000 -0500
Modify: 2017-06-06 07:07:31.000000000 -0500
Change: 2017-06-06 07:07:40.000000000 -0500
Birth: -
- Different ways to determine the size and age of a file
statdisplay the access time, modification time, or meta-data change time- can also get the using
ls -u,ls -t, orls -c
$ ls -tl *ob*
lrwxrwxrwx 1 beckbw G-814141 3 Jun 6 07:07 bobby -> bob
-rw------- 2 beckbw G-814141 0 Jun 6 07:07 bob
-rw------- 2 beckbw G-814141 0 Jun 6 07:07 robert
$ find -mtime <days>
$ find -mtime 1
$
$ find -mtime 0
./robert
./bob
./bobby
What about file size?
First, Create some files to play with
$cd test (if not already there)
$ for i in $(seq 0 10) ; do mkdir research_$i ; cd research_$i ; for j in $(seq 0 10) ; do touch data_${i}_${j}; done; cd - ; done
$ ls -R
.:
bob research_0 research_10 research_3 research_5 research_7 research_9
bobby research_1 research_2 research_4 research_6 research_8 robert
./research_0:
data_0_0 data_0_1 data_0_10 data_0_2 data_0_3 data_0_4 data_0_5 data_0_6 data_0_7 data_0_8 data_0_9
./research_1:
data_1_0 data_1_1 data_1_10 data_1_2 data_1_3 data_1_4 data_1_5 data_1_6 data_1_7 data_1_8 data_1_9
./research_10:
data_10_0 data_10_1 data_10_10 data_10_2 data_10_3 data_10_4 data_10_5 data_10_6 data_10_7 data_10_8 data_10_9
...
- Lets alter some files.
- We’ll replace a file with random data
$ cat /dev/random > research_6/data_6_7*** ctrl-c after a few seconds
- now how big is the file?
$ ls -lh research_6/data_6_7
- let’s copy a pogram and overwrite a file then make it executable again (
chmod)
$ cp /bin/ls research_5/data_5_6
$ chmod +x research_5/data_5_6
- now let’s see how
findexplores the meta-data
$ find . -executable
$
$ find . -size +20M
$
$ find . -size +20k
- find will execute a command for each file it finds
$ find . -size +20k -exec ls -lh {} \;
Example2: du disk Usage
duwill explore how much storage space a file or group of files takes up
$ du
4 ./research_10
4 ./research_7
4 ./research_5
4 ./research_0
4 ./research_4
4 ./research_9
27652 ./research_6
4 ./research_2
4 ./research_8
4 ./research_1
4 ./research_3
27696 .
- can we make it human readable?
$ du -h
4.0K ./research_10
4.0K ./research_7
4.0K ./research_5
4.0K ./research_0
4.0K ./research_4
4.0K ./research_9
28M ./research_6
4.0K ./research_2
4.0K ./research_8
4.0K ./research_1
4.0K ./research_3
28M .
- what if I just want the grand total?
$ du -sh .
28M .
Can I see how much of this disk is being used?
- use the
df(disk free) command like we did earlier
$ df /home
Filesystem 1K-blocks Used Available Use% Mounted on
129.114.58.7:/home 6673221632 802356224 5534554112 13% /home
- or human readable:
$ df -h /home1 Filesystem Size Used Avail Use% Mounted on 129.114.58.7:/home 6.3T 766G 5.2T 13% /home
Quota : artificial limit place on you disk usage
- So now I know how big files and disks are. Is there a way to find how much I’m allowed to use?
- let’s explore two commands:
quotaandlfs quotaquotawill show you how much/home1you are using
$ quota -s
Disk quotas for user beckbw (uid 827624):
Filesystem space quota limit grace files quota limit grace
129.114.58.7:/home
144K 10240M 10254M 158 750k 751k
lfs quotais a LustreFS command that you can apply to Lustre mounted systems like $WORK and $SCRATCH
$ lfs quota -h /work
Disk quotas for usr beckbw (uid 827624):
Filesystem used quota limit grace files quota limit grace
/work 10G 0k 1T - 6202 0 3000000 -
Disk quotas for grp G-814141 (gid 814141):
Filesystem used quota limit grace files quota limit grace
/work 12.8T 0k 0k - 3509052 0 0 -
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