feedback re tmpfs

Bill's LFS Login lfsbill at nospam.dot
Sat Jan 24 17:45:16 PST 2004


On Sun, 25 Jan 2004, Allard Welter wrote:

> Hello again,
>
> Thanks Bill for reminding me of the archives - informative and a lively
> discussion it was. I thought I'd repost these links in case anyone is
> interested.
>
> http://archives.linuxfromscratch.org/mail-archives/
> lfs-dev/2003-October/039106.html
>
> This link appeared somewhere in the thread and is still alive - again, very
> informative.
>
> http://www-106.ibm.com/developerworks/library/l-fs3.html
>
> Beside linux-2.4+/Documentation/filesystems/tmpfs.txt, I've also checked the
> libc manual, but here there is very little explanatory information
>
> So I've gone back to mounting tmpfs on /dev/shm as well as on /tmp and /var/
> tmp, although somewhere I read that mounting on /var/tmp is not such a good
> idea as stuff here is sometimes needed after reboot. I can't imagine this,
> why use a temporary directory then?

Are you mounting tmpfs all three places? If you want the effects of
that, I would think that symlinks from /var and /tmp would be more
desirable

ln -s /dev/shm /tmp
ln -s /dev/shm /var/tmp

Even then I'm not sure this wouldn't offer the potential for some goofs.
I'm thinking of mount seqyences. If tmpfs is not mounted when something
goes to write into /tmp (only X related I *think* ATM) or /var/tmp (not
even a guess here) there could be problems. Especially if the mount of
tmpfs hid something important in those directories.

It sounds to me like you need to look for Archaic's thread on a
read-only root FS in the archives. I thnk he had to deal with similar
issues and he's probably got some nuggets in there related to /tmp and
/var/tmp.

Personally, if you are not shooting for a read-only fs, I wouldn't worry
about /var/tmp. IIRC, only a very few very small files get put there
(like a seed for urandom which *should* be maintained across boots so
that entropy is maintained()?). It is important for some things
which depend on pseudo-random numbers.

>
> Regards - Allard.

-- 
NOTE: I'm on a new ISP, if I'm in your address book ...
Bill Maltby
lfsbillATearthlinkDOTnet
Fix line above & use it to mail me direct.



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