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https://issues.jenkins-ci.org/browse/JENKINS-3922?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=162143#comment-162143
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Jimmi Dyson commented on JENKINS-3922:
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The fix is present, but doesn't actually seem to fix the problem. Rather it
just improves the speed a bit, but it is still very slow compared to native SSH.
I have done some tests & this seems to be due to the library that Jenkins uses
for SSH - org.jvnet.hudson:trilead-ssh2:build212-hudson-5. Simple tests show
really slow SFTPing. I've experimented with [JSch|http://www.jcraft.com/jsch] &
get comparable speeds against native SFTP. I'm working on porting the SSH
slaves plugin to use JSch (which is released under a BSD-style license - any
compatibility issues there?).
One drawback of the JSch library is the lack of Putty key support. I don't know
if this is such a big deal as users can always convert Putty keys to OpenSSH
format keys using puttygen?
I notice that the org.jvnet.hudson:trilead-ssh2:build212-hudson-5 dependency
comes as transitive from jenkins-core. Should the SSH library actually be a
part of core dependencies?
> Slave is slow copying maven artifacts to master
> -----------------------------------------------
>
> Key: JENKINS-3922
> URL: https://issues.jenkins-ci.org/browse/JENKINS-3922
> Project: Jenkins
> Issue Type: Bug
> Components: master-slave
> Affects Versions: current
> Environment: Platform: All, OS: All
> Reporter: John McNair
> Assignee: Kohsuke Kawaguchi
> Priority: Critical
> Attachments: pom.xml
>
>
> The artifact transfer is currently a 3-4x penalty for the project that I am
> working on. I have reproduced the issue with a simple test pom that does
> nothing but jar hudson.war. I performed this test on a heterogeneous
> environment. Both master and slave are running Fedora 10, but the master is a
> faster machine. Still, it highlights the issue.
> Here are some stats (all stats are after caching dependencies in the local
> repos):
> Master build through Hudson: 19s
> Master build from command line (no Hudson): 9s
> Slave build through Hudson: 1m46s
> Slave build from command line (no Hudson): 16s
> To be fair we should at least add time to do a straight scp of the artifact
> from
> slave to master. The two nodes share a 100 Mbit switch:
> $ scp target/slow-rider-1.0.0-SNAPSHOT.jar master_node:
> slow-rider-1.0.0NAPSHOT.jar 100% 25MB 12.7MB/s 00:02
> Of course this example exaggerates the issue to make it more clear but not by
> too much. I originally noticed this in a completely separate environment that
> was all virtual. I reproduced this on two physical machines using a different
> switch and different ethernet drivers (both virtual and physical). The
> reproducibility plus the comparison against command line + scp leads me to
> suspect eager flushing.
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