SUMMARY : mirroring applications

From: Hardy, Chris (C.G.) (
Date: Sat Nov 22 1997 - 04:47:54 CST

Hello there

I know that this is not directly sun related and I apologise in advance

We have got a file server sitting on our main subnet at the moment that
contains a lot of applications that are mounted by machines around the
site. We are in the process of trying to upgrade the network and include
subnets locally. One of the problems now is that the users on these new
subnets have to mount the devices holding these applications across the
router. In order to reduce the local traffic and bandwidth utilisation
across the router, we would like to have copy of the tree holding these
applications on the subnet side of the router.

I am looking for a program that will take note of any change made on the
main-lan tree and copy the differences out to the subnet-tree. This has
only to be a one way application. I do not just want to tar up and ftp
the entire application tree every night as this is a waste of bandwidth
and will invoke a delay in updates

Any suggestions are welcome and I will summarise

Chris Hardy
UNIX Support
Nortel FWA


Mirror Applications
Thank-you to the people who responded to this query - I got a few
different Ideas - including the use of cache-fs, setting up ethernet
ports across the router instead of going through it, but mostly the idea
of using a sun facility called rdist.

The man pages for rdist were a bit tough to get through but I will try
to summarise what I found here.

Establish where on the remote-server that you intend to place the tree.
Once I did this I then set up a local (not NIS) account in this location
that had this as a home ac. ( You could use NIS, but it was easier to
use local accounts as then there is less paperwork - we have to apply
for NIS accounts).

You then create a distribution file as follows :

HOSTS = ( donutadm@npais437 )
FILES = ( tree )

        install -R ;

This distfile controls the creation of a mirror of the local tree "tree"
in the home account of donutadm@npais437. As donutadm on your local
machine run rdist ( the man pages will provide you with lots of switches
you could use) and a copy of tree will be installed in donutadm's
account on npais437.

Things were further complicated for me by the use of a Netapp filer -
but you can work around it - all that remains now is to create a script
that does all of this for you and to set up a cronjob to automate the
script -

I hope that this is straightforward enough for you


>Chris Hardy Email:
>Unix Administration Telephone +44 (0)1803-667390
>Regional Service Delivery Fax +44 (0)1803-662979
>Nortel FWA ESN 795-7390
>Devon, UK

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