Re: [Hypercontent-users] slow_hyperconent14

[Alex V. <av...@co...>]

Just an update on SFTP speed - some research reveals that there are =20
some fundamental issues with the SFTP protocol which limit its speed: =20=

SFTP implements its own packet technology, and every sent packet must =20=

be acknowledged before the the next packet is sent.  By one estimate, =20=

this ends up yielding a maximum throughput of only 17% of the available =20=

bandwidth, and is essentially unnecessary since the underlying TCP/IP =20=

protocol basically fulfills the same purpose.  JSch uses a 1k packet =20
size - by boosting this to 8k I saw a 15-20% speed increase.  Setting =20=

it much higher seems to yield errors.  SCP is free of this limitation, =20=

so I may look into a hybrid SFTP/SCP implementation, where SFTP is used =20=

for things like directory listings, and SCP for actual file transfer.

Alex

On Sep 22, 2004, at 11:44 AM, Ingmars Rubenis wrote:

> Hello!
>
> About version 1.4 hypercontent. We are daily building more than
> 1300 files about 15 times per day. We are going alive on the 28th of
> September. We are planing about 3000 http files. The site of =20
> university of Latvia is
> quit large site please see http://portal.lu.lv .
> The hyperconent 1.4 is very slow. My memory setting are:
> JAVA_OPTS=3D"-server -Xincgc -Xms512m -Xmx1024m -Xss128k =20
> -XX:MaxHeapFreeRatio=3D70 -XX:MinHeapFreeRatio=3D40 -XX:NewSize=3D256m =
=20
> -XX:MaxNewSize=3D256m -XX:SurvivorRatio=3D8
> -verbose:gc -XX:+UseLWPSynchronization"
> It is even difficult to go  through files in hypercontent. Build =20
> process
> hangs a couple times a day.  Also it is time consuming to upload gif
> files (it is ok with jpeg).  May be you
> could help us with that. I have updated ftp.jar from =20
> www.enterprisedt.com library with newer one.
> About j2ssh-core.jar. I think this is the slowest point  in your
> application (the build proces hangs because of this in my mind).  The =20=

> library is quite slow and old and there are a lot of
> bugs. We are going to replace the class SFTPFileSystemImpl with
> library from project http://sourceforge.net/projects/jsch/ . What do
> You thing? Here is rather old comparing between these libraries
>   =20
> http://nagoya.apache.org/eyebrowse/ReadMsg?listName=3Dcommons-=20
> de...@ja...&msgId=3D697314
>   Is it worth to try? Where is the main problem? Why is this
>   application so slow and build through sftp is not working as it
>   should?
> I think You should not use old libraries in Your project hypercontent
> 2.0 like j2ssh-core.jar. May be try
> http://sourceforge.net/projects/jsch/ instead.
> Why You are not using apache slide =20
> http://jakarta.apache.org/slide/index.html in the hypercontent 2 =20
> project?
> What do You think about apache cocoon and =20
> http://cocoon.apache.org/lenya/ ?
> How spring framework will act in the next release and velocity also?
> We would like that hypercontnet 2.0 would be as seperate applacition
> (war)(not bundled with tomcat). What is Your opinion? How we could =20
> help?
>
>
> About tomcat and uportal.
> As I understand from Your previos mail that tomcat is restarted daily?
> Is there any application startup script for uportal (after restart it
> is slow)? Is there any
> tomcat health checking system or may be .sh file?
>
>
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> Best Wishes
> Ingmars Rubenis
> LU
> University of Latvia
> Developer
> IT department
> (371) 7034736
>
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