Is it possible to do dynamically throttled UPDcast transmission? We need
to throttle the data flow to a Logic Innovations IP encapsulator (with
LI's documentation attached with their permission).
The udpcast mutlticast address is considered a single route to the IPE.
The IPE sends out flow-control messages (described in document) that
shows how many bytes are available for traffic for each route every 100
milliseconds in a multicastand comes from a user specified multicast of
its own. Attached is the LI document, again with the manufactures
permission. Also, you can contact Theo Aukerman, taukerman(a)logici.com
for any additional info.
I'm asking these questions because IF this is possible, then this would
be an almost complete framework for an open source Data-casting network,
and can be used for over the air data-broadcasting from any DTV
transmitter or any other system with null packets. I currently work as
an engineer for a TV station that does data transmission, but would like
to move to an open source model.
Please confirm my guess (or explain how to implement it).
I need a "sender-timeout", a period of time while sender waits for receivers
to connect, and if none are connected - sender exits without transmission.
The only way to implement this is shell/perl/... script, which starts
udp-sender with --min-receivers option and monitors its stderr. If no
"Starting transfer" is found during specified period of time - it kills
http://udpcast.linux.lu/cmd.html states that --nosync is the default
when writing to a file or a pipe, but this does not appear to be the
case; I verified with strace that udp-receiver open()s its output
file with O_SYNC unless you specify --nosync.
Running SuSE SLES10/SP2 and an image of about 17GB. When multicasting clients, performance appears to suffer from a excessive number of timeouts and/or retransmits. If the images are smaller this is not a problem, but we currently need them this size.
The errors appear frequently:
Timeout notSnasweed= notReady= nrAns=2 nrPart=3 avg 10193
We added the configs of rmem_default and rmem_max in the /tftpboot directory substructure in init.d for the client. It does seem to affect the speed, but still winds up bombing out on the big partition (~17GB).
It's an IBM blade center w/SAS drives which do not have cache.
Hi udpcast list!
I work as an IT technician and certainly one of the most invaluable
tools for my line of work has become the excellent open source cloning
app Clonezilla. I have found it many times faster than ghost in
creating images of NTFS partitions as well as being more reliable in
many cases too. AND its FOSS so- very cool tool indeed!
Clonezilla has a server-side counterpart app called drbl (diskless
remote boot Linux). drbl is still in beta but when its finished it
aims to provide functionality similar to Ghost Server, as found in
Ghost Solution Suite. drbl uses udpcast to do its broadcasting of
images over a network and the easiest way for people to try out drbl
is to download drbl-live from
I can't wait to be able to totally replace Ghost with clonezilla/drbl,
but I'm unable to switch from ghost server to drbl for 2 reasons
1- drbl-live server setup script/ ncurses GUI currently presumes you
have multicast capable hardware and doesn't offer a mode to utilise
udpcasts -brdcast mode easily yet but the author says he'll think
about adding this capability.
2- drbl-live also requires that you either enter a specific time to
wait or number of clients that have to connect or both. In my
experience with using ghost server to image many machines you will
know how many machines you WANT to image but you don't know how many
of them will actually be able to connect to the server due to hardware
failures and also you don't know just how long it will take to get all
the machines connected to the server. Hence, I want drbl-live's
Clonezilla server setup script to be able to work just like gs in that
after setting the network settings and selecting the image to be
broadcast etc. I would just select 'Listen for clients' or whatever.
Then I would have an indefinite amount of time to run around and TRY
to get everything connected to the drbl server. As each client
connects to the server, it would get registered on the drbl console.
When I've connected as many machines as possible, I would just be able
to hit a key to start the broad/multicast. Setting a definite amount
of time to wait or number of machines wouldn't work for me!
The author of clonezilla and drbl has told me that #2 isn't do-able
because this isn't supported by udpcast. Is he mistaken?
Thanks for your help!
I'm trying to clone several dell latitude laptops, but I can't seem to find
the correct driver for the hard drive (when i pick the default choice, I get
only "Other" in the partition list).
Is there a way to locate the correct one ?