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Questions tagged [concurrency]

The tag has no usage guidance.

0
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0answers
19 views

Jenkins/Nginx returning 404 when concurrent requests made from jenkins

I am running nginx latest docker image to access nginx. I have 2 jenkins jobs triggered at the same time - which make a GET request to nginx and get the data. When the two jobs ran at the same time, ...
0
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2answers
63 views

AWS codedeploy: parallel or concurrent deployments

I'm currently experimenting with AWS codedeploy and noticed that there can be only one deployment running at the same time. I have six applications (in the AWS codedeploy sense) each with one ...
0
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0answers
87 views

How many concurrent TCP connections or sockets can be handled by a web server for e.g in a chat application

I find that all the chat servers either use sockets like WhatsApp or long polling to provide the to and fro flow of messages. I wonder how so many concurrent TCP connections or sockets are maintained ...
0
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1answer
38 views

Does the maximum amount of open descriptors in a server include it's children?

I know that Linux limits the maximum amount of open descriptors, usually to 1024. Now say I need to create a server which will handle more than 1024 users, 2000 for example, without tampering with the ...
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0answers
13 views

Oracle Database - Grant/Revoke High Concurrency

We have an Oracle 10g release 2 database running on a production environment. It's experiencing a lot of concurrency, as Sql Developer 17.4 "Waits for past 1 hour" graph shows. When the database is ...
2
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0answers
282 views

Gunicorn does not repondes more than 6 requests at a time

To give you some context: I have two server environments running the same app. The first, which I intend to abandon, is a Standard Google App Engine environment that has many limitations. The second ...
0
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4answers
84 views

Tips on technology for one program, many concurrent http clients on small host? [closed]

What technology could be used for one application to serve many simultaneous users on a small resource-constrained host (eg: Rasbperry Pi or similar)? That is, it doesn't need a general purpose web ...
1
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0answers
108 views

Understanding clients-server max-concurrent-connections and TIME_WAIT state

I know there are a lot of questions and also answers around the TIME_WAIT state of a socket connection, but somehow non of them (or maybe from an experts perspective all of them) help me to understand ...
2
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1answer
322 views

Google Cloud SQL / App Engine concurrency limits

I've been using Google App Engine to host my APIs and keep banging up against the limitation of concurrent database connections. The docs say that you can only have up to 12 concurrent connections per ...
3
votes
1answer
791 views

How to circumvent siege concurrency socket select timed out

Being trying to test load capacity of a web site. I am using an aws ubuntu xenial server t2.micro as test client and have SIEGE 3.0.8 and apache benchmark Version 2.3 while ab -c 100 -n 100000 url ...
1
vote
1answer
347 views

Terminal Command to find maximum allowed TCP/IP connection on a port in Apache server(CentOS)

Is there any terminal commands to check the maximum allowed number of concurrent TCP/IP connections can be done in Apache server with CentOS??
0
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1answer
2k views

Is it advised to close MySQL connection after every query

I have some sort of web crawler with PHP, which crawls the web and stores information about the pages in the database, now the thing is, loading pages takes a lot of time, and on top of that my script ...
2
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0answers
38 views

How does a server (e.g. web) manage multiple request/connections? [closed]

I read that apache has a solution to create new thread per new request, but I still have some questions. How is possible that one server can manage thousands (even a milion connection - depends from ...
0
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1answer
79 views

Apache delays serving an empty html file while processing a concurrent request

I have a website, which queries a Varnish server, which queries an Apache server, which queries a db server. At 07:00:00, a request is send to the Apache server, which triggers a db request that ...
-4
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1answer
527 views

What is the internet Bandwidth needed to support 2000 concurrent requests?

For one our projects, we need to calculate the internet bandwidth required to support 2000 concurrent requests/per second. Following is the scenario detail: If 1 user accesses the page, the ...
1
vote
3answers
867 views

Why is method that uses gevent in a mod_wsgi deployed Flask api raising error about switching threads?

I am trying to deploy a Flask api via Apache/mod_wsgi. The api uses Gevent to provide concurrency for a recursive method. However, it is throwing the following error [Mon Feb 08 12:05:37 2016] [error]...
2
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2answers
2k views

Postfix - rate limit outgoing concurrent connections to one machine/ip

I need to limit postfix outgoing connections for specific mailservers, but it seems to me that posfix's limiting is based on domains? What if there is one mailserver for more domains? I tried to find ...
5
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1answer
9k views

How to allow more than two simultanous sessions on Azure

One of our servers is on Azure and we are remotely connecting to it. Unfortunately Azure allows only two users to be logged in at the same time. When the third user tries to log in, he is given the ...
3
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1answer
9k views

Limit concurrent connections to Postfix server

I'm having trouble limiting the number of concurrent connections from the same client to my Postfix server. Limiting the maximal number of concurrent processes, from the same or different clients, is ...
0
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1answer
424 views

Server is not responding when single connection is blocked

I'm not sure how to properly specify this problem, I'm not really a server expert. I will be glad to provide additional data on demand. I have a PHP web-application running on Ubuntu Server with ...
0
votes
1answer
143 views

Excel 2013 Power Pivot RemoteApp - limited by 4 concurrent users? [closed]

We're trying to use Excel 2013 (64bit) + Power Pivot via RemoteApp. The problem we're having is basically the same as described this TechNet thread. 4 concurrent users have no problem using Power ...
0
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0answers
572 views

xmpp openfire connection manager not working

I have downloaded the connection manager here .In windows I have extracted it to program files in C drive and edit the conf/manager.xml to set domain and password. I also enabled connection manager in ...
2
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1answer
338 views

apache mpm_worker server failed to respond

I'm trying to update our current Apache 2.4.9 configuration from using prefork to worker mpm. I'm doing some simple load testing using jmeter to compare the performance between the 2. My first test is ...
0
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1answer
970 views

Apache httpd response time increase with concurrent connections

I know many questions have been asked on this subject, but I didn't find an answer to help me. I'm trying to have Apache httpd answer 200 concurrent connections. I'm testing with jMeter, fetching a ...
0
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1answer
1k views

Ask nginx to handle requests from the same IP in parallel?

I have an application internal to my company that needs to be very fast per client, because the clients are so limited and the whole thing is internal. So, the client is expected to send so many ...
1
vote
1answer
320 views

Throttling a user across multiple datacenters

I'm trying to implement a throttling feature on nginx, that is shared across multiple servers across multiple datacenters. I would like to know what would be the best practice for building this. For ...
2
votes
1answer
3k views

Server's maxconn parameter in haproxy

I'm using HAProxy in production to balance queries to a series of server instances that can only process 1 query at a time (by our own decision). Knowing that I set the maxconn parameter in the server ...
2
votes
2answers
3k views

How to determine POSIX advisory file locks are working in simfs in the VM I'm using?

I'm looking for a command-line utility or some other way to test effectiveness of file locks, specifically POSIX advisory locks (which aren't only for POSIX, btw) in a Linux filesystem. Specifically, ...
2
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2answers
16k views

How does server handle multiple clients on the same port? Multiple sockets or multiple ports? [closed]

I have a misundertanding about some networking theory and because I couldn't find a definitive answer online (most resourceas are theory and theory etc without concise examples) I'm asking here. ...
2
votes
1answer
467 views

Plotted ab results of node, cluster and nginx, odd results?

I did a test with ab -n 10000 -c 1000 against node.js with different configurations, each returning the string Hello World!. Results seems odd to me. X axis is the number of requests, y is the ...
1
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0answers
247 views

Fail with ab test with nginx, two workers and 1024 connections?

I'm doing some tests with nginx 1.4.1 and Node.js 0.10.5 on my development machine (P8700 Dual Core 2.53Ghz, 4Gb RAM running Xubuntu x64). Unfortunately I can't do ab with 100000 requests with a ...
3
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2answers
491 views

How to lock concurrent access to a shared webservice from multiple webservers?

Our production environment consists in n Apache web servers accessed by browsers via a frontal load balancer. Very typical. 99% of our HTTP requests are gracefully handled by this parallelized ...
0
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1answer
1k views

iSCSI and NFS file locking and concurrency

I've got a linux host that need to mount a data share located on a NAS. The choice is between NFS v3 (NAS limitation) and iSCSI. The initial idea was to have a NFS mount to the file server that ...
1
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3answers
1k views

Several Cron at same minute

I'm installing a bunch of Magento shops on a webserver. Every website has a cron job that Magento uses to update its stuff -- it takes 3-4 seconds to complete. The instructions tell to set it to run ...
0
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1answer
8k views

Optimizing Apache for large concurrent requests and static files

OK, I know I'm asking a question that's been asked multiple times before (e.g. here - Serve millions of concurrent connections and static files?) but there appears to be no concrete solutions, so I ...
0
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3answers
85 views

What framework is good for delivering data that is commonly changed in a few second and is assessed by lots of people (similar to stock quote)? [closed]

I am only familiar with php and javascript and I guess php is not good at serving large amount of concurrent request. I would be grateful if someone can introduce me to more appropriate framework for ...
2
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2answers
5k views

Heavy write to Galera cluster - table locked, cluster practically unusable

I set up Galera Cluster on 3 nodes. It works perfectly for reading data. I have done simple application to make some test on the cluster. Unfortunately I have to say that the Cluster fails totally ...
3
votes
1answer
909 views

Apache Benchmark is slow from public network, magnitudes faster locally. What are some things I do to speed this up?

I am testing my Linode Ubuntu 14 64bit server out, it's the most basic server available from them. I am using Apache Benchmark to test the server, as well as a multithreaded script I wrote in Python, ...
0
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2answers
381 views

Simulating 1000 concurrent downloads

I'd like to simulate 1000 concurrent downloads of a single file from Cloudfront. I figured I'd setup ~10-20 xlarge EC2 instances for this. Is there an obvious way I'm missing to trigger this at the ...
3
votes
2answers
5k views

Tracking down “Connection reset” errors in Linux

I'm handling large numbers of concurrent downloads (approx. 500 per server) using Java. All the files are being downloaded from Amazon S3, and the downloading server is an EC2 m1.large instance. ...
12
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5answers
21k views

NGINX timeout after +200 concurrent connections

This is my nginx.conf (I've updated config to make sure that there is no PHP involved or any other bottlenecks): user nginx; worker_processes 4; worker_rlimit_nofile 10240; pid ...
0
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1answer
1k views

How do concurrent filesystems work? [closed]

From learning about how filesystems use transactions and logs to make sure that the disk is in an atomic state even after there's been a system crash, I've become curious about how filesystems deal ...
0
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1answer
247 views

How do i get concurrent asp.net on linux?

-edit2- It turns out asp.net (i dont know if its mono specific) blocks if the url and ip address are the same. Its nonblocking if i run it from my local machine and server at the same time. I have ...
2
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1answer
217 views

IIS 7.5 on Windows 7 Ultimate

I am looking to install Windows 7 Ultimate and run IIS 7.5 on it. However, I would like to know exactly what my limitations will be with this setup. While researching this topic various resources ...
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0answers
1k views

tomcat max number of threads

I have a very confusing scenario.. We are using tomcat6 to host an internal application. In server.xml file maxthreads attributes is set to 150 but if I log on to the manager, in "http-8080" section I ...
0
votes
1answer
764 views

postfix concurrency limit with round robin dns

Take the following internal round robin dns setup mymta.com. IN A 172.31.1.1 mymta.com. IN A 172.31.1.2 mymta.com. IN A 172.31.1.3 mymta.com. IN A 172.31.1.4 mymta.com. IN A 172.31.1.5 mymta.com. IN ...
0
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1answer
304 views

Limit on concurrent connections: Determined by webserver or database?

Does the webserver or is it the database that limits the number of concurrent connections?
2
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5answers
1k views

Many concurrent SSH commands in a bash script?

My Bash-Foo is not strong. Right now I have something like function update_project { for i in server-{1,2,3,4} ; do echo "Updating $i" ssh $i "git pull" done } The number of servers is ...
3
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3answers
444 views

Super simple high performance http server

I´m building a url shortener web application and I would like to know the best architecture to do it in order to provide a fast and reliable service. I would like to have two separate servicies in ...
1
vote
1answer
604 views

proper concurrent users estimation case studies

I've been asked to size a web architecture for an excessive number of concurrent users ( hundreds of thousands ). I'm having a hard time convincing these people that unless you are in the top 5 of ...