mounted file system show 50% free but it is empty

[Richard Hollenbeck]

I have a FS that showed 50% used but there is nothing in it. (HP-UX 11i) I tried to unmount it and it returned "busy". After fuser -cu, I found three processes and killed them. I could then umount the file system. I fsck'd it and then remounted it and it showed 100%. Can anyone explain what might have happened? This is rather urgent. Thank you.

[Sanjay_6]

Hi,

It is possible that a process was writing to a log file on this filesystem and the file was deleted. Since the process was still running the space was still occupied by the deleted file. When you killed the process, it released the space and doing an unmount/fsck/remount reclaimed the space. Though the umount/fsck/remount was not necessary.

You can use lsof to find any process that is holding a file open within a filesystem. To download and install lsof, if you don;t have it installed, try

http://hpux.cs.utah.edu/hppd/hpux/Sysadmin/lsof-4.73/

This link from itrc might be helpful,

http://www1.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000072657091

The itrc doc id is KBRC00008039.

Hope this helps.

Regds

[A. Clay Stephenson]

I assume that when you say it showed 100% that means 100% free. When a file is unlinked (rm'ed - more or less) the link count is reduced by 1. If that link count is now zero, the entry is removed from the directory. However, the space occupied is not actually freed until all process which had the file open either close the file or terminate. Man 2 unlink for more details.