Translucent File System

2007-12-25 7:14:00

Summary: Use of the Translucent File System under SunOS 4.1.

I got a variety of responses, but the most complete was from Earle Poseur,

and I am enclosing it for reference:

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>Has anyone used the Translucent File system that is SUPPOSEDLY available

>under 4.1 SunOS?

It's not `supposedly available'; it is available (as long as `options TFS'

and `options LOFS' are in the kernel configuration file for the currently

running kernel, that is). I'm using it right now:

poseur:2:30 [/tmp] % mount | egrep -v 4.2

yehtmae:/export/vol/X.V11R4 on /usr/share/src/local/X.V11R4 type nfs (rw,hard,intr,noquota)

/ on /tmp_mnt/Tfs_native type lo (rw)

/tmp_mnt/Tfs_empty on /usr/share/src/local/X.V11R4 type lo (rw)

/usr/share/src/local/.X.V11R4-build on /usr/share/src/local/X.V11R4 type tfs (rw,bg)

I mount my vanilla X11 R4 source tree from my Sun386i onto my Sun-3, and then

I do a TFS mount of another directory heirarchy (based at the directory

/usr/share/src/local/.X.V11R4-build) on top of that NFS mount. When a TFS

mount is done, it automatically adds the `/ on /tmp_mnt/Tfs_native' loopback

mount as well.

>I have several applications for it (local vs global

>manpages being one of them), but there appears to be a dearth of documentation

>on it, (and it may actually not even exist?). In particular:

>

> 1. The man pages say that the daemon tfsd is started by inetd,

> but I can't find any reference in /etc/inetd.conf or /etc/services

> to the program OR network service number and protocol that

> it should use.

Here's the /etc/inetd.conf entry:

..

#

# The TFS server provides the ability to do TFS filesystem mounts.

#

tfsd/1-2 dgram rpc/udp wait root /usr/etc/tfsd tfsd

> 2. The 4.1 Installation manual says to see the System and Network

> Admin manual for a complete description, but I don't find any

> description.

Yep. Bug in the documentation. An oversight; the TFS documentation didn't

make it into the System and Network Administration manual like the Install

manual claimed.

> 3. Is is unclear whether the front writable directory must be a

> separate file system or whether it can be a directory on a currently

> mounted file system.

It can be a directory on a currently mounted filesystem, as per my example

above. Here's my /etc/fstab:

..

/dev/sd0c /usr/src/local 4.2 rw 1 6

yehtmae:/export/vol/X.V11R4 /usr/src/local/X.V11R4 nfs rw,hard,intr,noquota 0 0

/usr/src/local/.X.V11R4-build /usr/src/local/X.V11R4 tfs rw,bg 0 0

Here's the end of my /etc/rc:

..

mount -vat tfs

                                date

exit 0

Given this scenario, I can still always refer to `/usr/src/local/X.V11R4' and

below as I would normally; any changes/compilations/etc. to that heirarchy is

really made in /usr/src/local/.X.V11R4-build and below. I made that TFS mount

point a `dot' directory name so that it would be more hidden. I never need to

refer to that directory tree by name, I see the virgin source tree *and* any

changes made to it, as if I'd done it directly in that tree. Greatest thing

since sliced bread :^)

        - Greg Earle

          Sun Microsystems, Inc.

          JPL on-site Software Support Engineer

          earle@poseur.JPL.NASA.GOV - or - earle@Sun.COM

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Thanks to:

"Anthony A. Datri" <convex!datri@uxc.cso.uiuc.edu>

mailrus!umich!dgsi!brian@gatech.edu (Brian Kelley/1000000)

Mike Pearlman <canuck@rice.edu>

Kerien Fitzpatrick <fitz@frc2.frc.ri.cmu.edu>

Todd Pfaff <todd@flex.Eng.McMaster.CA>

earle@poseur.jpl.nasa.gov (Greg Earle - Sun JPL on-site Software Support)

edsr!jcn@uunet.uu.net (Jim Niemann)

dgsi!paulh@umich.edu (Paul Haas/1000000)

- Doug Neuhauser, doug@seismo.gps.caltech.edu, (818)356-3993

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