Hi,
Now It's Ok !!! It was the memory ! I change slot's memory I test during 4 hours and no problem. I make new images et restore it with no fail ! But 80 Mbps with no compression 25 Mbips with 3/1 lzop compression 17 Mbips with 3.6/1 compression It's faster without compression !!!
I hope, I'll find a multicast ftp to increase the speed in case of quasi empty partition...
Thank a lot
Pierre
Good to hear it was resolved. When you said that it aborted at random points, I thought hardware could be involved, and compression would push the heat, etc more than straight data flow.
Be careful comparing the data transfer rate. That doesn't measure how fast you are writing the info to disk, and in the end, that is the only thing that matters in the performance of udpcast. Time the job with a clock/watch and compare the times.
In my experience, udpcast is just as fast than an FTP based solution when comparing the same image and hardware on all ends.
lzop uncompression will perform much better than gzip on older CPUs and possibly on other platforms like Sun sparc. Otherwise gzip is fine for something like a P4 generation target client.
At our institution, using gzip, we write 40GB to P4-M notebooks in 34 minutes, regardless how much non-zeroed data there is to write (e.g. Windows only, or Windows + Linux partition = same time to write), and regardless how many notebooks we image in a session.
--Donald Teed
On Wed, 28 Dec 2005, Pierre CANAL wrote:
Hi,
Now It's Ok !!! It was the memory ! I change slot's memory I test during 4 hours and no problem. I make new images et restore it with no fail ! But 80 Mbps with no compression 25 Mbips with 3/1 lzop compression 17 Mbips with 3.6/1 compression It's faster without compression !!!
I hope, I'll find a multicast ftp to increase the speed in case of quasi empty partition...
Thank a lot
Pierre
D Teed wrote:
Be careful comparing the data transfer rate. That doesn't measure how fast you are writing the info to disk, and in the end, that is the only thing that matters in the performance of udpcast. Time the job with a clock/watch and compare the times.
Indeed. The bandwidth displayed by udpcast is the bandwidth needed to transmit the *compressed* data. If you have a very compressible disk, the limiting factor now becomes the disk read speed, and compressed (network) bandwidth will drop. However, the useful bandwidth (uncompressed data), which is not displayed, will rise.
[...]
At our institution, using gzip, we write 40GB to P4-M notebooks in 34 minutes, regardless how much non-zeroed data there is to write
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Normally, if everything works correctly, it should be quicker to transmit images which contain lots of zeroed data. However, in such case, the *displayed* bandwidth (network bandwidth) will be lower, because such data still needs to be read from the disk, and udp-sender will end up waiting for the disk, rather than the network.
Regards,
Alain