Root filesystem 100% full

[gaf at blu.org (Jerry Feldman)]

I agree here except in to context of temporarily moving those directories 
and restoring prior to shutdown. It is a very dangerous operation. 
I've done this on Unix. It is very dangerous. 
Normally, /etc does not contain very large files, so it is not important. 
/dev sometimes contains some big files if you mistype /dev/null. It should 
not contain any real files of any significant seze, just a make file, a 
couple of symlinks. 

/bin is sometimes a symlink to /usr/bin, and is normally not critical in 
single user mode. /sbin is very definitely critical. It contains all the 
static binaries. Without it you can't run. 

Another condidate is /lib. Again, caution. /lib/modules is used during and 
before single user mode. 

The bottom line is that if you need to temporarily free up some space for 
your program to continue, you can take a risk, but remember that the risk 
is that your system will become unbootable. You can move /boot/vmlinux if 
it is in the root file system, but the same cautions apply. Depends how 
much you want your program to complete. 

IMHO, any program that takes that long to run should have some type of 
checkpoint/restart capabilities. There are exceptions. I am working with a 
customer who has code that takes a couple of weeks (on a multi-processor 
system with multiple gigs of memory). 
On 10 Jun 2002 at 16:03, Derek D. Martin wrote:
> /bin, /sbin, and /etc should *ABSOLUTELY NEVER* be moved off the root
> filesystem.  Many things which are required to boot the system are
> located in those directories, and they will not be available to init
> and its various subprocesses if they are not on the root filesystem.
> For example, your system will not be able to enable swap at boot time,
> because the program that does this is /sbin/swapon, which will not be
> mounted until after swap is normally turned on if it isn't on the root
> filesystem.

--
Jerry Feldman <gaf at blu.org>
Associate Director
Boston Linux and Unix user group
http://www.blu.org PGP key id:C5061EA9
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