designing /usr/local/{bin,etc,lib}
Steve Clark
clark at cme.nist.gov
Tue Dec 25 02:49:15 AEST 1990
>>>>> 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
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