To monitor a log file I have to connect to an ssh connection and redirect the output of the log file(let's call it RemoteLog.txt) out to a local machine so it can be read by a java program and put on a GUI.
Right now I have the output redirected out of the ssh connection and onto the local machine with the command:
ssh remote#ip.address tail logs/RemoteLog.txt -f > ~/Log/LocalLog.txt
and everything works fine technically with one exception: for some reason LocalLog.txt only gets updated with the changes to RemoteLog.txt every 35 seconds to the millisecond.
It doesn't matter the number of changes to RemoteLog, the number of lines specified with the tail command, or using the >> operator vs the > operator; there is always a 35 second delay between updates of LocalLog.txt while RemoteLog is constantly updating.
Does anyone have any clue why this might be?
An activator template project was created by
activator new rest-benchmark simple-rest-scala
cd rest-benchmark
activator clean stage
target/universal/stage/bin/rest-benchmark -Dplay.crypto.secret=1234
the template can be found here
Then I run ApacheBench to get a rough idea of playframework's throughput:
ab -n 20000 -c 5 http://127.0.0.1:9000/books
which always give similar result - timeout at around 16.3k-th request:
apr_socket_recv: Operation timed out (60)
Total of 16345 requests completed
However, if I run ab with -k KeepAlive:
ab -k -n 20000 -c 5 http://127.0.0.1:9000/books
The benchmark was able to complete.
I have several questions:
Why always timeout when Keep Alive is absent? Shouldn't play be able to handle requests regardless of this header? Or is it my OS keep the connection open, hence no further requests can be processed?
Why around the 16300-th request? Is it related to ulimit?
If missing Keep Alive will cause connection timeout, what can I do in production?
Edit: Switched to play 2.5.4
Edit2: Changed app launch command as marcospereira suggested, observing same result
I have a process using https. I found its PID using ps and used the command lsof -Pan -p PID -i to get the port number it is running on.
I need iftop to see the data transfer. The filter I am using now is
iftop -f "port http 57787".
I don't think this is giving me the right output.
Can someone help me the right filter to use with iftop so that I know the traffic going through only this port?
I can see 2 problems here:
1/ Is that a typo? The correct option for filtering is -f (small "f"). -F (capital "F") option is for net/mask.
2/ Though not explicitly stated by iftop documentation, the syntax for filtering seems to be the pcap one from the few examples given (and using ldd I can see that yes, the iftop binary is linked with libpcap). So a filter with http is simply not valid. To see the doc for pcap filtering syntax, have a look at pcap-filter (7) - packet filter syntax man page. In your example, a filter such as "tcp port 57787" would be OK. pcap does not do layer 5 and above protocol dissection such as http (pcap filters are handled by BPF in the kernel, so above layer 4 you're on your own, because that's none of the kernel business).
All in all, these looks like iperf bugs. It should refuse your "-F" option, and even with "-f" instead exit with an error code because pcap will refuse the filter expression. No big deal, iftop is a modest program. See edit bellow.
EDIT:
I just checked iftop version 1.0pre4 source code, and there is no such obvious bug from a look at set_filter_code() and its caller packet_init() in iftop.c. It correctly exit with error, but...
Error 2, use the "-f" option, but your incorrect filter syntax:
jbm#sumo:~$ sudo iftop -f "port http 57787"
interface: eth0
IP address is: 192.168.1.67
MAC address is: 8c:89:a5:57:10:3c
set_filter_code: syntax error
That's OK.
Error 1, the "-F" instead of "-f", there is a problem:
jbm#sumo:~$ sudo iftop -F "port http 57787"
(everything seems more or less OK, but then quit the program)
Could not parse net/mask: port http 57787
interface: eth0
IP address is: 192.168.1.67
MAC address is: 8c:89:a5:57:10:3c
Oops! "Could not parse net/mask: port http 57787"! That's a bug: it should exit right away.
Environment:
Unix client and unix server.
Tool used : curl.
Client/Server should ignore the time wait time (2 *MSL ) when establishing connection.
This is done by executing the following commands :
sysctl net.ipv4.tcp_tw_reuse=1
sysctl net.ipv4.tcp_tw_recycle=1
Local port must be specified so that it can re-used.
Start the connection.
Example : while [ 1 ]; do curl --local-port 9056 192.168.40.2; sleep 30; done
I am still seeing the error even though it should have ignored time wait period.
Any idea why this is happening?
I have a server where I store data from Mac A and Mac B.
I use rsync to keep the files updated between my Macs.
I run the following code unsuccessfully
#!/bin/zsh
# to copy files from my server to my folder
rsync -Pav $Masi:~/private/ ~/Dropbox/Courses/math/
# to copy files from my folder to my server
rsync -Pav ~/Dropbox/Courses/math $Masi:~/private/
I get the following error message
ssh: connect to host port 22: Connection refused
rsync: connection unexpectedly closed (0 bytes received so far) [receiver]
rsync error: unexplained error (code 255) at io.c(600) [receiver=3.0.5]
ssh: connect to host port 22: Connection refused
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255) at io.c(600) [sender=3.0.5]
I have ssh keys in place so the connection should work, since I can use scp without problems.
How can you use rsync between my server and one of my Macs?
I used to do a lot of this. Just ran a test, a few suggestions.
Spell out your entire user#host pattern
Run the ssh connection sans the rsync first, you may need to first approve your fingerprint
You do not seem to pass a flag to protect extended attributes, this can yield broken files on OS X. If you do not need resource forks, you are OK, but most of the time you do need them.
My test case:
$ rsync -Pav ~/Desktop/ me#remote.example.com:~/rsyc-test
In that case, all the files within ~/Desktop were copied to the remote host, in my home dir. Since the directory 'rsyc-test' did not exist, it was made for me. I had a .app on my Desktop, it made it over, surprisingly, it works. Even some .webloc files made it and appear to work, though I do not trust it.
I would strongly suggest adding in the -E flag
-E, --extended-attributes
Apple specific option to copy extended attributes, resource
forks, and ACLs. Requires at least Mac OS X 10.4 or suitably
patched rsync.
I ran a new test, moved a Interarchy bookmark to my desktop, I know for a fact these break if they are copied sans resource forks. Running without the -E versus with the -E, there is a difference of 152 bytes in xfered data. The first file on the remote machine did not work, the second transfered file did work.
I can not help but notice in your example one of your paths is ~/Dropbox so this may all not matter, since DropBox, the app, does not at all support resource forks currently, though I hear there are plans to in the future.
You also are not sending in the --delete flag, if your end goal is a mirror of your data, you are not getting that, if your end goal is backups that continually grows, keeping everything that was ever on the source, the lack of --delete is good.
Other notes:
You can exclude those silly .DS_Store files
--exclude '.DS_Store'
You can also set rsync up in a way to be a true mirror, so you would not need to run your other command, see the man page for details.
My final working command to shove the Desktop of my laptop to a remote machine:
$ rsync -PEav --delete --exclude '.DS_Store' ~/Desktop/ me#remote.example.com:~/rsycn-test
Check "$Masi". Is that the hostname you are trying to reach?
Try the following command to debug it:
rsync -e 'ssh -v' -Pav $Masi:~/private/ ~/Dropbox/Courses/math/
The Connection refused usually happens when there is a connection issue to the remote (e.g. firewall).
In your case the problem is that $Masi variable is empty. If it's not variable, use Masi.
As per this error:
ssh: connect to host port 22: Connection refused
Notice the double space above after the host word.
the connect to host message doesn't say to which host, so you're trying to connect to empty host. So it sound like a typo in the host name.