Re: AW: AW: [gt-user] What encryption algorythmus does GridFTP use with -data-channel-private?

Tue, 18 Sep 2007 09:05:54 -0700 



[EMAIL PROTECTED] wrote:

Just to prevent misunderstandings: I'm not complaining that the performance
is less than without encryption. The GridFTP User Guide clearly states that
the performance impact of those options is significant. I'm just curious why
scp is so much faster, when I see no real difference in the functionality.



I suspect that this is a BWDP issue.  make sure you set -tcp-bs properly.  Try it with 16 megabytes 
for starters.



Though the performance improvement when using multiple streams is curious.
The CPU load of the GridFTP process also increases with more streams.


check out this paper:
http://www.globus.org/alliance/publications/papers/gridftp_infocom07.pdf


the summary is that we can put each stream on different CPU for parallel processing the data 
channels.  for max benefits this does require a threaded build of the gridftp server (and for your 
numbers it looks like you are not getting max benefit).




Those are the commands
scp -c aes128-cbc bibgrid1lx:/mnt/sw_src/rhel5/isos/* /scratch/
globus-url-copy -r -vb -data-channel-private -p 4
gsiftp://bibgrid1lx.eu.boehringer.com/mnt/sw_src/rhel5/isos/ file:///scratch/

If you want it detailed: the numbers are im MB/sec as reported by
globus-url-copy when it has finished the transfer. P is the number of
parallel streams.

        File            p = 0   p = 2   p = 4   p = 8   p = 16
default 1       21,39   37,45   41,68   49,36   41,54
                2       27,77   28,77   26,30   25,11   25,52
                3       24,71   22,68   26,18   21,77   22,22
                4       22,96   25,25   22,94   27,46   24,53
                5       23,33   30,94   22,70   21,59   18,96
        average 24,03   29,02   27,96   29,06   26,55

safe            1       9,13    17,82   18,62   18,24   19,39
                2       9,34    16,26   18,89   20,39   19,05
                3       9,35    16,22   17,04   20,86   19,20
                4       9,66    15,73   17,97   19,56   19,33
                5       9,32    15,98   18,01   19,53   20,49
        average 9,36    16,40   18,11   19,72   19,49

private 1       3,23    4,80    6,67    8,24    8,41
                2       3,26    4,76    6,84    8,43    9,24
                3       3,26    4,76    6,87    8,41    8,79
                4       3,28    4,78    7,00    8,28    8,85
                5       3,25    4,78    7,07    8,34    8,65
        average 3,26    4,78    6,89    8,34    8,79

And one scp run:
1       27,40
2       25,50
3       26,30
4       26,80
5       24,30
Avg     26,06

-----Ursprüngliche Nachricht-----

Von: John Bresnahan [mailto:[EMAIL PROTECTED] 
Gesendet: Dienstag, 18. September 2007 16:54

An: Assfalg,Christian (APER) BIP-DE-B
Cc: [EMAIL PROTECTED]; [email protected]
Betreff: Re: AW: [gt-user] What encryption algorythmus does GridFTP use with
-data-channel-private?


can you send the command you use to transfer the file?


[EMAIL PROTECTED] wrote:

I'm transferring five ISO images, about 600 MB each, 3.1 GB in total. The
numbers are the ones that GridFTP reports when run with the -vb option, so

I

guess they do not include startup delays. The same applies for scp.

-----Ursprüngliche Nachricht-----

Von: Richard Wellner, Jr. [mailto:[EMAIL PROTECTED] 
Gesendet: Dienstag, 18. September 2007 16:32

An: Assfalg,Christian (APER) BIP-DE-B; [email protected]
Betreff: Re: [gt-user] What encryption algorythmus does GridFTP use with
-data-channel-private?


How large a file are you transferring?  GridFTP takes more time for

start-up

and the performance gains become evident only with large files.

rw2

On 9/18/07 2:47 AM, "[EMAIL PROTECTED]"
<[EMAIL PROTECTED]> wrote:


Hello!

I've been doing some performance measurements with GridFTP and safe /

secure

data channels, that is using the -data-channel-safe and

-data-channel-private

options.

This showed that the performance between two 2.2 Ghz Opteron machines on

the

same switch topps at about 10 MB/sec for -data-channel-private and -p 2 /

-p

4. I am wondering what kind of encryption algorythm and implementation
GridFTP uses?

Scp reaches transfer rates of up to 35 MB/sec on the same scenario using

the

aes128-cbc cipher. This is actually quite near the maximum disk IO I

observed

using iostat, and can only be achieved on subsequent runs. I'm not shure
wether CPU or disk is actually the bottleneck here.

Regards,
Christian Aßfalg


























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