Re: [anonymous] [bugs #11124] ls stats symbolic link targets (fwd)

[Bob Proulx]

Mark H. Wilkinson wrote:
> Bob Proulx wrote:
> > Hmm...  I don't think I would call that common practice.
> 
> Hmm; I thought I recalled Solaris 8 leaning in that direction for
> workstation users: each user has their home directory on the local disk,
> but can login to other machines if needed. It's been a while though.
> Perhaps that only works for small networks too...

I have no direct knowledge of Solaris.  But on other systems the
configuration is left entirely up to the local admin.  The choice of
using an automounter or not and how to configure it are local
conventions.  In particular we use host maps at my site.  But everyone
else I chat with think those are bad and use indirect maps.  So to me
it seems indirect maps are the most common case.

An indirect map would be something like this:

  *  -rw  &:/u/&

This is just one possible configuration.  (I needed something concrete
for discussion.)  If that were mounted on /home and all user's home
directories physically placed in /u on their home machines but were
logically specified as being under /home then all users can log into
all hosts and the home directory looks the same on every machine.

For example a user 'bob' would have a home ~bob specified as /home/bob
on all machines.  User bob's machine would have an alias 'bob' and
bob's actual physical home directory would be mounted /u/bob on bob's
home machine.  With wildcards expanded that becomes:

  bob -rw bob:/u/bob

That mounts bob:/u/bob, an alias to my real machine name, at /home/bob
and everything looks normal no matter which machine I log into.  Using
indirect maps in this way coupled with NIS/YP maps for the passwd file
enable a centralized administration of systems and user data.  That is
a big advantage for many sites.

Again, I did not think that the OS vendor actually specified any of
this.  It is all local configuration and convention.

At my site the convention is host maps.  Every user's ~ directory is
mounted at /net/hostname/home/user.  This works fine too for the case
just listed.  But there are problems dealing with a disk farm on a
server with many disks.  The filesystems are discovered at mount time
and on a loaded server may time out and lose a mount point.  At that
time the only way to recover is to "unbusy" the mount point and try
again.  That can be tricky in practice and few people understand it
well enough to accomplish it.  Therefore direct maps for filesystem
servers tends to work better.

Bob