strange problem

[absi]

i have a strange problem reported by my database
group
/db fs have filled up to 18GB space(df )[18.5 GB total
fs size].
du -sk command when run on same fs shows
15.5 GB space utilized.
But when db is shutdown nearly 1.5GB relaesed
Db group said no unusual growth of database files
no log files creation!!!
they are saying "fragmentation within fs"
But i want to have some comments from my group fellows
here!!! before running defrag command on fs...
Db---> Progress
Aix4.3.2
Absi

 

[IgorFranco]

Hi !

I think i can help u.
Please send me the output of the df -k and du -sk command for this filesystem. I don't understand what u mean about 1.5Gb released ...
Try run fuser -xcu /fs and see if some process is still on the filesystem, after stop on DB is done.

What i can tell u is, there is big differences between df and du commands. They usually don't report the same value ...

Best Regards
Igor Franco

 

[hackey37]

Just to chime in on the differences between df and du---
df maintains the meta-data that du does not. IN other words, stuff like inode information and other such data about your files gets lumped into your df total and that is why df is bigger. du accounts for only filesizes themselves if am recalling correctly. HTH, hackey37

 

[absi]

dears thanks for ur propmt responses
what i mean by saying 1.5 GB released is that
after db shutdown df begin to show nearly 16.5 Gb full
for that filesystem.
That is nearly 1.5 gb less space occupied than what it appeas when db is running.
Also it does not happen all the time
i feel that DB creates some file which are removed
when db is shutdown...but no support from database
group on this idea.....
Can defragmentation help in this regard????
Absi

 

[gileb]

Hi,

Do you know that in unix, within a prog, if a file is "deleted" before the close of the file descriptor, the file is REALLY deleted when program is stopped. It means that when a prg uses a file, and somebody deletes the file (no lock on it), the room taken by the file is given back to system when the process stops only and then strange df and du dont show the released space until the end of the process itself.
Is that problem occuring each time you stop the db or only some times ?

 

[absi]

hi gileb,
just sometimes only!!!!!
Absi

 

[gileb]

For me it sounds like a temporary file being used and deleted before the closing of the file desc. That would explain the fact it is released only when process stops.