Speeding up secure file transfers (scp/sftp) Any ideas?

[Jason Cannon]

The transfer speed between ftp and scp/sftp is quite noticeable. What can I do to improve the performance of scp/sftp.

Thanks!

Jason

[Pete Randall]

Jason,

I would expect that the difference is caused by the extra CPU cycles consumed by the encription algorithm. The way to address this is to minimize CPU contention, increase CPU horsepower, or switch to Itanium, which is supposed to be great at encription.


Pete

[RAC_1]

What did you check?? Check following.

lanadmin -sx "ppid_of_nic"
Are the speed setting and uplex setting correct on server and on switch side??

Aaprt from that, what version of ssh are you using?? How you have configured it??

Anil

[Stuart Browne]

What sort of speed differences are we talking about here, over what sort of comms network?

Are you talking about 10k/s slowed down to 9k/s, or something more dramtic?

Also, how big are the files you're transferring?

[Jason Cannon]

More info:

For testing I'm using two (practically) idle L3000-7x's. As far as ramping up processors, I never got over 25% CPU utiliziation while doing the scps tests. I ran netperfs in and out of each server, with no problems.

T1471AA A.03.91.002 HP-UX Secure Shell

# lanadmin -sx 0
Speed = 100000000
Current Config = 100 Full-Duplex AUTONEG

Test of 34024 KB file:
ftp: 6.47 MB/s 5 sec
scp: 2.4 MB/s 14 sec

Jason

[Andrew Cowan · Accepted solution]

Try running an simple ftp of a test file and if it performs substantially better it is probably down to the en/decryption algoritms. Try changing the "cipher" schemes in "ssh(d)_config". This can have a dramatic effect on some systems. If you use top or glance you can monitor this in real-time.

[Michael Selvesteen_2]

1. Try HP Secure Shell (A.04.00.000) which incorparates better buffer enhancement to increase the speed of data transfers.

2. Using the weak ciphers like Arcfour will increase the speed (not recommended if your network path is highly speculative )

(scp -c user@host1: user@host2:)

3. http://www.psc.edu/networking/projects/tcptune/

4. http://www.psc.edu/networking/projects/hpn-ssh/

Hope this helps.

[Jason Cannon]

I used Andrew and Michael's idea of using a different cipher and that did the trick.

Thanks for everyone's help!

Jason