Re: Migrating database from Windows to Linux

I think the problem might be the encryption scp uses in contrast to SMB. Which most probably explains the speed difference there.

Speed of encryption/decryption in scp also heavily depends on cipher used and cpu's available (sending/receiving party). So you could experiment with different ciphers.

Try using RC4 as cipher .. you'll probably see an increase in throughput example scp -c arcfour

(note - rc4 not so secure ;-) )

Lastly - you might want to experiment with compression in on scp (might decrease throughput or increase depending on cpu load)

cheers
Kurt

Van: "tim evdbt" <tim.evdbt_at_gmail.com> Aan: justin_at_n0de.ws, JBECKSTROM_at_gcrta.org Cc: "oracle-l" <oracle-l_at_freelists.org>, "oracle-db-l" <oracle-db-l_at_groups.ittoolbox.com> Verzonden: Vrijdag 3 maart 2017 07:08:01 Onderwerp: Re: Migrating database from Windows to Linux

Jeff,

Please consider first measuring the throughput between the servers using the [ https://iperf.fr/ | iPerf3 ] package. Doing so should provide the maximum bandwidth to be expected on that particular network segment, and if it is possible to improve that bandwidth somehow, iPerf is a good way to measure.

Also, please consider using the [ https://www.slac.stanford.edu/~abh/bbcp/ | bbcp ] package, pretty much the fastest and most full-featured method of copying files over TCP.

Hope this helps!

-Tim

On 3/2/17 22:00, Justin Mungal wrote:

It would be interesting to see how fast SCP is between your Linux servers, and then comparing that speed with transfers from Windows to Linux with an SCP client (assuming all else is equal). SCP between Linux servers has always seemed fast to me, while using WinSCP has always seemed slow. I've never had to migrate large files with WinSCP so I've never put much thought into it. But if SCP between Linux servers is much faster then you at least know that the issue is not the SCP protocol itself (although a client may be using a version that may have something to do with the issue). I agree with Hans; you should give other clients a shot.

On Thu, Mar 2, 2017 at 1:37 PM, Beckstrom Jeffrey < [ mailto:JBECKSTROM_at_gcrta.org | JBECKSTROM_at_gcrta.org ] > wrote:

BQ_BEGIN We are copying our database files and have noticed some strange results.

Copying from Windows to a Linux server using putty (pscp) is orders of magnitude slower than copying to a samba drive and then moving the files to the Linux server. Can someone suggest places to look as to why copying directly to the Linux server is so much slower?

Jeffrey Beckstrom
Lead Database Administrator
Information Technology Department
Greater Cleveland Regional Transit Authority 1240 W. 6th Street
Cleveland, Ohio 44113

BQ_END

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