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.
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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