redesignde the unix-like system directory

Bob Proulx bob at proulx.com
Wed May 6 19:55:56 UTC 2020


Tim Daneliuk wrote:
> Arne Steinkamm wrote:
> > >> /cloud, various cloud applications
> > >> /net,  network information and server information, etc.
> > Looking at a flat layout like this one gives me a feeling, that
> > most people forgot that it's a real bad idea to have a 
> > external mounted directory in the root directory... easy way to make
> > a system unresponsive in case of a network problem.
> 
> Can you say a bit more about why this is so?

Assume NFS for simplicity.  A mount point at the /nfsmount1 directory.
Then run "ls -l /".  That needs to stat(2) each entry in / and hits
/nfsmount1 with stat(2) which if the nfs server is not responding
cannot return an answer to the query.  A lot of daemons and cron jobs
will assume that the file system root and all entries in there are
available and will trigger this problem as a byproduct of their
operations.  I am just describing "ls -l" as the simplest way to
trigger the issue.  "NFS server not responding."  This can be a reason
for a system load of hundreds or thousands as process slots fill up
with stuck processes blocked waiting for I/O from an unresponsive server.

However in the proposal I think the entries I quoted were for use as a
subdirectory and not to have a mount point directly in root.

> > I keep the traditional filesystem layout

+1.  I prefer the traditional file system organization.

Bob


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