[SOLVED] Clearing /tmp

niels.horn · 12-27-2010, 09:13 PM

I would definitely use -atime.... If it has not been accessed 'x' days, I remove it.

catkin · 12-27-2010, 09:31 PM

Quote:

Originally Posted by spoovy

Yeah you're right. I'm not sure the man page makes sense in that respect.

Shouldn't it be -atime rather than -mtime though? As the hidden files won't be modified by rc.local therefore won't be spared when your code cleans /tmp. But they will presumably be "accessed" by the rc.local script when it checks if they are present or not.

Or am I misunderstanding ?

AFAIK find resets atime on files and directories it accesses. -atime will, of course not work on file systems mounted with noatime which is commonly used for performance.

Cleaning /tmp from rc.local will also remove any quota data, along with anything created as a result of running all the other boot scripts.

If /tmp is not on the / file system then it cannot be cleaned at the rc.S position described in the OP; it must be cleaned later, ideally just before "# Enable swapping again. This is needed in case a swapfile is used"

2handband · 12-27-2010, 10:02 PM

I realized that I'm being an idiot... of course it didn't work at that point. I have /tmp in a separate LVM partition. I'm gonna try placing it elsewhere and get back to you.

niels.horn · 12-28-2010, 03:23 AM

Quote:

Originally Posted by catkin

AFAIK find resets atime on files and directories it accesses.

no, it wont...
You can do a simple check with "ls -l --time=atime"

Quote:

Originally Posted by catkin

-atime will, of course not work on file systems mounted with noatime which is commonly used for performance.

Not sure if it's really so common. I only use 'noatime' on memory sticks etc. (if they're not FAT).

Toods · 12-28-2010, 04:23 AM

I put the following entry in 'fstab' so that all contents are deleted after each shutdown:

Code:

tmpfs            /tmp             tmpfs       defaults         0   0

I've never encountered any problems with this approach.

Bill.

catkin · 12-28-2010, 05:37 AM

Quote:

Originally Posted by niels.horn

no, it wont...
You can do a simple check with "ls -l --time=atime"

Thanks for the correction

I would have tested if all my file systems were not mounted with noatime. Given that atime is not restored by find, atime is even less use than I thought it was! AFAIK tar and cpio do restore atimes ... ?

GazL · 12-28-2010, 05:44 AM

Can't speak for tar, but with cpio you have to specify the "-a" option to preserve the access time.

edit:

At least that's according to the info page, however, from a quick test, specifying -a on a cpio -o causes the ctime to change, and not specifying -a doesn't seem to affect the atime, so the info page may be wrong on that one.

tronayne · 12-28-2010, 08:16 AM

Just for the heck of it:

Code:

fubar-trona-/home/trona: mkdir stuff
fubar-trona-/home/trona: stat stuff
  File: `stuff'
  Size: 4096            Blocks: 8          IO Block: 4096   directory
Device: 807h/2055d      Inode: 130942      Links: 2
Access: (0755/drwxr-xr-x)  Uid: ( 1000/   trona)   Gid: (  100/   users)
Access: 2010-12-28 08:41:32.447262540 -0500
Modify: 2010-12-28 08:41:32.447262540 -0500
Change: 2010-12-28 08:41:32.447262540 -0500

That is, make a directory, atime, mtime and ctime are all the same.

Code:

fubar-trona-/home/trona: find stuff -print
stuff
fubar-trona-/home/trona: stat stuff
  File: `stuff'
  Size: 4096            Blocks: 8          IO Block: 4096   directory
Device: 807h/2055d      Inode: 130942      Links: 2
Access: (0755/drwxr-xr-x)  Uid: ( 1000/   trona)   Gid: (  100/   users)
Access: 2010-12-28 08:41:56.710261990 -0500
Modify: 2010-12-28 08:41:32.447262540 -0500
Change: 2010-12-28 08:41:32.447262540 -0500

Execute find on the directory, atime changes, mtime and ctime do not.

Code:

fubar-trona-/home/trona: print "Hello, world" > stuff/junk
fubar-trona-/home/trona: stat stuff
  File: `stuff'
  Size: 4096            Blocks: 8          IO Block: 4096   directory
Device: 807h/2055d      Inode: 130942      Links: 2
Access: (0755/drwxr-xr-x)  Uid: ( 1000/   trona)   Gid: (  100/   users)
Access: 2010-12-28 08:41:56.710261990 -0500
Modify: 2010-12-28 08:42:21.007262534 -0500
Change: 2010-12-28 08:42:21.007262534 -0500

That is, create a file in a directory, directory atime changes, mtime and ctime do not.

Code:

fubar-trona-/home/trona: find stuff -print
stuff
stuff/junk
fubar-trona-/home/trona: stat stuff
  File: `stuff'
  Size: 4096            Blocks: 8          IO Block: 4096   directory
Device: 807h/2055d      Inode: 130942      Links: 2
Access: (0755/drwxr-xr-x)  Uid: ( 1000/   trona)   Gid: (  100/   users)
Access: 2010-12-28 08:42:32.098263399 -0500
Modify: 2010-12-28 08:42:21.007262534 -0500
Change: 2010-12-28 08:42:21.007262534 -0500

This is, execute find, directory atime changes, mtime and ctime do not.

Code:

fubar-trona-/home/trona: stat stuff/junk
  File: `stuff/junk'
  Size: 13              Blocks: 8          IO Block: 4096   regular file
Device: 807h/2055d      Inode: 130943      Links: 1
Access: (0644/-rw-r--r--)  Uid: ( 1000/   trona)   Gid: (  100/   users)
Access: 2010-12-28 08:42:21.007262534 -0500
Modify: 2010-12-28 08:42:21.007262534 -0500
Change: 2010-12-28 08:42:21.007262534 -0500

That is, execute find on file in directory, file atime, mtime and time do not change.

All that being as it is, I really like Toods approach -- blow the entire thing away at shutdown. Methinks that's what I'm going to do and forget about all this other stuff.

Hope this helps some.

GazL · 12-28-2010, 08:32 AM

Yep, the tmpfs approach is a good way to do this and I've used it in the past. You can always use /var/tmp for stuff that won't fit in memory should you need to.

In fact, a lot of the stuff that people do in /tmp probably belongs in /var/tmp anyway.

vivanguarda · 01-09-2011, 11:45 AM

In spite of having solved in this topic I 'd like to deep knowledge about possible problems deleting /tmp , /sys/tmp/, cached and log rotations arquives .

I use slackware 13.1 exploring root and another user called: “normal”. Right after a fresh install there are inside /temp : kde-normal/, kde-root/, ksocket-normal/ ksocket-root/, kde-socket. Is safe to delete it? And what should I do to delete log arquives?