請問一個關於size的問題

[watermelonyu]

if i want to see disk used size i always used the command du -sk or bdf

in bdf /opt/pdmcorp as below:



Filesystem kbytes used avail %used Mounted on

/dev/vg00/lvol3 2097152 169696 1912456 8% /

/dev/vg00/lvol1 298928 43992 225040 16% /stand

/dev/vg00/lvol6 4194304 696600 3470560 17% /var

/dev/vg00/lvol9 4194304 622960 3543448 15% /var/adm/crash

/dev/vg00/lvol5 2621440 1215408 1395088 47% /usr

/dev/vg00/lvol7 524288 119192 402832 23% /tmp

/dev/vgtest1/lvmtest

5120000 1849614 3072642 38% /test1

/dev/vg00/lvol4 2621440 2059152 558240 79% /opt

/dev/vg00/lvol11 10485760 4330226 5963182 42% /o9i

/dev/vg00/lvol8 524288 32768 487696 6% /home

/dev/vg_wo9i/lv_wo9i01

67133440 30570608 36277248 46% /wo9i/datafile

/dev/vg_wo9i/lv_wo9i02

26214400 15466844 10579632 59% /wo9i/index

/dev/vg_wo9i/lv_wo9i03

11476992 2167088 9019654 19% /wo9i/archive

/dev/vg_wmeta/lv_wmeta

6283264 1188520 5054968 19% /opt/pdmwrg01



but in du -sk /opt/pdmwrg01

1184760 /opt/pdmwrg01



used du -sk /opt/pdmwrg01 is 1184760

used bdf /opt/pdmwrg01 is 1188520



what is the correct ? and can you tell me the different ??

[watermelonyu]

Obviously there is a difference in how du and bdf behave.

This may occur if we touch open files.



"du" shows output in a positive view: it shows the number of currently allocated

blocks and counts the blocks you've just deleted as free.

"bdf" has a more negative perspective: it shows the free disk space available.



The difference is here: if a still-active process has allocated blocks (such as

for a logfile that you've just deleted), "bdf" counts these as still occupied.

This won't change until the process closes the file ("deallocates the blocks")

as it usually happens when the process terminates.



Document id: TBRIXKBRC00001367

[watermelonyu]

http://www.hp.com.tw/ssn/unix/9908/unix990801.asp



非常詳盡的解說.

[watermelonyu]

可以用 fuser -u /opt/pdmwrg01, 看看到底是什麼 process 還在使用