[gridftp-user] "-pp" Parameter in globus-url-copy for GT 4.2.1

[John Bresnahan]

The optimization from -pp still transfers files in serial, it just overlaps the control channel 
latency with the previous sessions data channel.  The performance of each file transfer will not 
change much, but the delays in between will.  Overall you should see an enhancement.

If you do not, the -cc option will have the simultaneous transfers you expect.

Graham Jenkins wrote:
> Guys, I'm trying to transfer large numbers of 300Mb files from one side
> of Australia to the other using a command like:
> 
>  globus-url-copy -vb -udt -p 4 -pp file:///data/ftp/tmp/d1/ sshftp://graham@arcs-df.ivec.org/var/tmp/graham/
>  
> And what I'm seeing in the logs is:
> --
> Source: file:///data/ftp/tmp/d1/
> Dest:   sshftp://graham@arcs-df.ivec.org/var/tmp/graham/
>   v252l_Pk_058_224710.lba
>     207618048 bytes        39.60 MB/sec avg        39.60 MB/sec inst
>     320004096 bytes        40.16 MB/sec avg        41.22 MB/sec inst
> 
> Source: file:///data/ftp/tmp/d1/
> Dest:   sshftp://graham@arcs-df.ivec.org/var/tmp/graham/
>   v252l_Pk_058_102440.lba
>     232521728 bytes        44.35 MB/sec avg        44.35 MB/sec inst
>       .. etc.
> --
> 
> In other words, each file is sent in its entirety before transfer of the
> next one starts.  And some timing tests reveal that the net transfer
> time for a batch of files is identical, whether or not I specify "-pp".
> 
>>From reading the documentation, I would have thought that multiple files
> would be sent in simultaneity.  So what am I doing wrong here?
>