Bulk File Transmissions - options

[brian_31]

We have to send bulk data between applications on a HP-UX 11.0 Server. How about SFTP for Bulk file transmission? Another option was connect-direct. Between connect-direct(costs $$) and SFTP can someone tell me which is better? pros/cons. Please advise.

Thanks

Brian.

[Sivakumar TS]

Dear brian,

What is the data size that u need to copy ?

SFTP should be good enough.

WIth Regards,

Siva.

[Arunvijai_4]

I could say, SCP is the best option available for copying securely in HP-UX. You can also use SFTP, i would rather prefer scp.

-Arun

[Sยภเl Kย๓คг]

Hi,

What's the distance b/w these two server, What's the bandwidth of data transmission. If you have fair enough bandwidth go with arun, scp good one., else sftp.

Regards,
Sunil

[brian_31]

I thought SCP would be very slow compared to SFTP. Could someone tell me what are the advantages of SCP over SFTP please?

Thanks

Brian.

[Greg Vaidman]

scp and sftp should have identical performance. they both use the underlying ssh protocol. the only difference really is the syntax - scp can transfer a file using a very simple syntax, whereas you have to provide a short script to use sftp.

That said, both sftp and scp have significantly poorer performance when compared to plain ftp on a local LAN transfer, due to the cpu overhead of encryption and possibly compression. Across a slow WAN, sftp/scp can actually perform better or similarly to ftp because network latency negates some of the cpu overhead, and the compression reduces the total traffic. So, definitely make sure you're using compression with sftp/scp on a WAN.

In addition, you may want to investigate the tcp transmit and receive windows (set with ndd) if throughput is important. I found upping the values from a default 32k up to 80k yielded a 2.5x improvement in throughput on our particular pipe, but you may need to experiment with different values because everyone's environment is different. BTW, don't just set these parameters to huge numbers, because there is additional memory overhead associated with every tcp connection when you up these parameters.

Good luck!
--Greg

[Greg Vaidman]

I should clarify - the two parameters I alluded to are tcp_xmit_hiwater_def and tcp_recv_hiwater_def.

e.g.,

ndd -get /dev/tcp tcp_recv_hiwater_def

ndd -set /dev/tcp tcp_recv_hiwater_def 65536