[vox-tech] RH keeps crashing

ME vox-tech@lists.lugod.org
Mon, 22 Apr 2002 10:15:54 -0700 (PDT)


On Mon, 22 Apr 2002, Robert G. Scofield wrote:
> When you guys talk about the filesytems being full, do you mean that the hard 
> disk is full?  I once completely filled up a Red Hat system to the point 
> where I'd get error messages that it could not write my files because there 
> was no room.  However, Linux worked flawlessly under these conditions unlike 
> Windows which begins to crash with 150 megs or so of empty space left.

try "df":

# df
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/sda1              4032092     81300   3745968   2% /
/dev/sda2              6048352   2009152   3731960  35% /usr
/dev/sda5              8064272     60664   7593956   1% /var
/dev/sda6              6048320    353896   5387184   6% /usr/local
/dev/sda7              2016016       136   1913468   0% /tmp
/dev/sda8             25165430   3946231  19903076  17% /home
/dev/sdb1             66196261    211984  62445963   0% /usr/export/array1

Each moutpoint (the "mounted on" column, has a device mounted/assigned to
it. The "Use" column shows % use.

When we talk about filesystems getting full, we often refer to a
particular volumne/mount-point getting filled up.

The most common ones to cause problems include:
/var/log (important one to not let get filled up - you want logs! The
          life's blood of an admin.)
/var     (Important as well especially if you dont have a separate
          mpuntpoint for /var/log)
/tmp     (Used to create special temp files by services and programs. The
          most common problem with /tmp filled up is certain new service
          just wont start, but can lead to crashes if the services cant
          deal well with problems)
/        Some people use monolithic filesystems (meaning everything
          mounted on one mount point "/". In cases like these, all of the
          above are under "/" and you should not let "/" be too full.
/etc     Config files are mostly left here, and non of the services should
          try to mod stuff here. Of course password programs (changing
          passwords) and user control stuff does mod stuff here, as would
          certain GUI based control panels for system stuff. You should
          not let /etc get full - This is almost *always* part of "/" and
          not a separate mountpont. Why? You cant see what fiesystems
          to mount if /etc/fstba is not available to the "/" filesystem
          when it is mounted. 

For the others:
/home
/usr
/usr/local

There should be fewer system problems with these getting filled up. Having
them get filled up is still not a good idea, but is frequently less
serious than all of the other items listed above. These last items getting
filled up will often impact the admin's ability to upgrade software (/usr,
/usr/local) and the user's ability to run applications and save items to
disk (say bash wants to write the ~/.bash_history or netscape wants to
write to its cache in ~/.netscape/cache/...)

There are more reasons tan the above for not letting filesystem approach
being full or getting full.

Last comment in this message... Some filesystems on some OS will report
100% full when they really are not. 1-5% of the volume size may be saved
for admin/root writes. On other OS, they may only allow up to 95/99% of
the volume to get full and not let normal users write at that point but
instead only allow an admin to write. For these problems it is a good idea
to try to keep most volumes to well below 80% full when possible or risk
the above problems.

-ME
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