jake at vapourforge
Apr 28, 2009, 2:13 AM
Post #23 of 24
(3963 views)
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just a quick "make it easy" suggestion
lsof | grep "/tmp"
should spit out what's open in /tmp for you (otherwise your going to get
bazillions of results)
it can take a while to get results (10-20 seconds)
Shane Kerr wrote:
> On Mon, 2009-04-27 at 19:23 +0200, Andrea Brancatelli wrote:
>
>> Il giorno lun, 27/04/2009 alle 08.14 +1000, Josh Marshall ha scritto:
>>
>>> What I noticed is that running du -hs on the drive shows that there is
>>> plenty of space free, so I'm thinking that somewhere a temporary file is
>>> being deleted while still open and being written to. So the file listing
>>> entry is deleted but the space is not made available until the file
>>> handle is closed.
>>>
>> du shows no space being used, while df shows that there's 0% of space
>> free...
>>
>
> This is "normal" in Unix-land. If one deletes a file that an application
> has open, the application can continue to use it indefinitely. The space
> is freed up as soon as the last application closes the file.
>
> So a quite normal way for an application that needs temporary space to
> work is to create a file, open it, then delete the file. It then has a
> relatively secure temporary file that it doesn't have to worry about
> other applications reading or writing.
>
> In Linux one can see this with the "lsof" command:
>
> shane [at] shane-asus-lapto:~$ cat test.c
> #include <stdio.h>
> #include <unistd.h>
>
> int main()
> {
> FILE *fp = fopen("/tmp/xxx", "w");
> unlink("/tmp/xxx");
> sleep(300);
> return 0;
> }
>
> shane [at] shane-asus-lapto:~$ cc test.c
> shane [at] shane-asus-lapto:~$ ./a.out &
> [1] 6381
> shane [at] shane-asus-lapto:~$ lsof -p 6381
> COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
> a.out 6381 shane cwd DIR 0,29 12288 107171 /home/shane
> a.out 6381 shane rtd DIR 8,6 4096 2 /
> a.out 6381 shane txt REG 0,29 11034 532605 /home/shane/a.out
> a.out 6381 shane mem REG 8,6 1502512 2562 /lib/libc-2.9.so
> a.out 6381 shane mem REG 8,6 135680 2542 /lib/ld-2.9.so
> a.out 6381 shane 0u CHR 136,1 3 /dev/pts/1
> a.out 6381 shane 1u CHR 136,1 3 /dev/pts/1
> a.out 6381 shane 2u CHR 136,1 3 /dev/pts/1
> a.out 6381 shane 3w REG 8,6 0 532522 /tmp/xxx (deleted)
> shane [at] shane-asus-lapto:~$ kill 6381
> shane [at] shane-asus-lapto:~$
> [1]+ Terminated ./a.out
>
>
> If you do NOT specify a process ID with "lsof" then it shows the files
> opened by all processes. You may want to do this as root, and then look
> for files in /tmp that are deleted, and find the offending process
> (which I guess we already know is dbmail-imapd).
>
> --
> Shane
>
> _______________________________________________
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>
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