designing /usr/local/{bin,etc,lib}

[Steve Clark]

>>>>> On 21 Dec 90 23:07:39 GMT, arnold at mango.synopsys.com (Arnold de Leon) said:

Arnold> I was referred to the a paper presented at the Usenix LISA IV,
Arnold> "The Depot".  IT is apparently available for anonymous ftp
Arnold> at durer.cme.nist.gov (129.6.32.4) as ~ftp/pub/depot.lisa.ps.Z

It is, indeed.  As one of the authors of this paper, I just wanted to
clarify one thing.

Arnold> Working with the example "perl", the installation on "server"
Arnold> would look like 
Arnold>         /export/depot/.primary/perl/plat-sun4-OS4/bin/perl

Arnold> The clients will "see" this as
Arnold>         /depot/.primary/perl/plat/bin/perl
			or
Arnold>         /depot/perl/bin/perl

The .primary/.develop directories are intended to be visible only in
the server's view.  They serve two purposes: 1) Organizational: they
distinguish the primary use copy(ies) of a package from the
development/testing copy(ies), and 2) Technical: We wanted the server
to be able to use a depot in the same manner as any other client, i.e.
to compose a client view via NFS mounts.  In the absence of .primary/,
a server would mount /depot/perl onto /depot/perl.  This gives NFS
fits when another client comes along and tries to mount /depot/perl
from that server.  Pushing stuff into /depot/.primary/perl on the
server allows the client view to be composed on the server without
obscuring the actual origin from other clients.

Arnold's approach of putting stuff under /export on the server is very
appealing to me.  I've never gotten around to trying it, but it seems
like the "right" way to avoid the collision I described above.  With
or without /export, though, the client view should not contain
.primary: The client sees the perl binary as /depot/perl/bin/perl.

Arnold> Aside:  I would expect that in this example that perl would be
Arnold>		have been configured to expect itself to be installed
Arnold>         in /depot/perl/{bin,lib}

Yup ... that's 'zactly right!

Arnold>         o Shared libraries and associated problems

We have the X11R4 shared libraries (libX*.so.*) in
/depot/X11R4/arch/lib.  There are symbolic links in /usr/local/lib
which point to these libraries.  Some users prefer to bypass
/usr/local entirely, putting /depot/*/arch/bin on their PATH and
setting LD_LIBRARY_PATH to pick up the shared libraries directly from
/depot/X11R4/arch/lib.

Arnold>         o Performance

Sorry ... we have no hard performance numbers, but the symlink
overhead on startup certainly seems insignificant (~80 clients, ~4
depot servers).

--
-steve
------------------------------------------------------------------
Steve Clark
National Institute for Standards and Technology (formerly NBS)
clark at cme.nist.gov		..uunet!cme-durer!clark
(301)975-3595 / 3544