Questions tagged [latency]

Latency is the time period between a signal being sent and a signal being received

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120 votes
9 answers
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How much network latency is "typical" for east - west coast USA?

At the moment we're trying to decide whether to move our datacenter from the west coast to the east coast. However, I am seeing some disturbing latency numbers from my west coast location to the east ...
Jeff Atwood's user avatar
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16 votes
1 answer
69k views

How to troubleshoot latency between 2 linux hosts

The latency between 2 linux hosts is about .23ms. They are connected by one switch. Ping & Wireshark confirm the latency number. But, i dont have any visibility into what is causing this latency. ...
Jimm's user avatar
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74 votes
8 answers
269k views

Why is the response on localhost so slow?

I am working on a tiny little PHP project for a friend of mine, and I have a WAMP environment setup for local development. I remember the days when the response from my local Apache 2.2 was immediate. ...
Peter Perháč's user avatar
20 votes
6 answers
30k views

How does geography affect network latency?

I have the option of hosting our database/web server at a managed hosting company on the East Coast (US) or one on the West Coast (US). Our company is based out of New York City, and both hosting ...
neezer's user avatar
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11 votes
1 answer
11k views

difference between taskset and cpuset

I'm trying to reduce the latency of my linux network application. I've learned that there are two tools for "binding" a program to particular CPU core: taskset and cpuset. Which one should I prefer? ...
John Linberg's user avatar
9 votes
3 answers
12k views

Why do tracert latencies not add up to ping latency?

One might expect the sum of the tracert latencies to equal 267ms:
pulsar's user avatar
  • 193
6 votes
8 answers
21k views

Latency in Internet connections from Europe to USA

I'm looking for a (cheap) Web hoster. Basically all the hosting providers that I can find, and match my requirements are located in the USA. But my target audience is in (Western-)Europe, I know for ...
GvS's user avatar
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38 votes
3 answers
49k views

Data obtained from ping: is it round trip or one way?

I have 2 servers, each in two separate locations. I need to host an application on one, and the database server on the other. From the app server, if I ping the database server, on average I get ...
Phil's user avatar
  • 523
29 votes
7 answers
44k views

Speed up SFTP uploads on high latency network?

I'm trying to transfer a set of large files internationally using SFTP, but I am finding my international partner can't get upload speeds above ~50k despite very good connections on either side. We ...
nick_eu's user avatar
  • 391
18 votes
3 answers
29k views

Do changes in SPF records take time to propagate?

I'm setting up SPF records for my domain, and am not getting the results that I expect. It's quite possible I'm making some sort of mistake, but first I'd like to ask: does it take time for the ...
Daniel Griscom's user avatar
14 votes
2 answers
40k views

Low latency TCP settings on Ubuntu

There is a server for measurements running on Ubuntu in my lab. And there is C program, which receives data through TCP connection and should as soon as possible send a reply. Configuration CPUs: 2 ...
Alex V's user avatar
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13 votes
6 answers
45k views

sssd and ldap authentication cache

On our box running OpenSUSE 12.2 we have installed OpenLDAP and sssd daemon. We are using these two services for user authentication. Recently we created a script which creates new web-users for our ...
Seth Rayer's user avatar
7 votes
2 answers
3k views

Does routing distance affect performance significantly?

When I say routing distance, I mean on a global scale. For instance, if my target audience is in China, do I look for a host within China?
gAMBOOKa's user avatar
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5 votes
5 answers
13k views

finding the best network latency between two countries

I know there are many tools to test for bandwidth and latency, but they all rely on having at least one host from which you can run those tests. I wonder whether there's an online source or some ...
Yoav Aner's user avatar
  • 581
5 votes
6 answers
14k views

Intermittent high ping/latency problem

I have been working with my ISP (which is a WISP, actually Fixed Broadband Wireless) trying to figure out why I intermittently get high latency. The latency is detectable in online games and other ...
Hugh Jeffner's user avatar
4 votes
3 answers
4k views

Route traffic to node with lowest latency in HAproxy

Is it possible to route requests via HAproxy to a server that has the lowest latency from the source IP? This seems like a much needed requirement but I can't seem to find anything. My problem is ...
rehanift's user avatar
4 votes
1 answer
4k views

How do I test my internet connection speed via a Microsoft Windows Terminal?

I currently have two production servers. One running Windows Server 2003 and the other Windows Server 2008. When I open the Reliability and Performance Monitor I see a Network section that only goes ...
nu everest's user avatar
4 votes
2 answers
11k views

Apache has a long lag before responding

I have an Apache server on CentOS that occasionally takes 1-5 seconds to serve a file, including a text file that is 2 characters. I have a JMeter test that gets a few different types of files, and ...
kjc26ster's user avatar
  • 193
3 votes
3 answers
4k views

Terminal server performance over high latency links

Our datacenter and head office is currently in Brisbane, Australia, and we have a branch office in the UK. We have a private WAN with a 768k link to our UK office and the latency is at about 350ms. ...
holz's user avatar
  • 187
2 votes
1 answer
2k views

How to apply `fq_codel` to balance traffic in multiple VLAN connections?

I have an Ubuntu server connected to multiple VLAN networks over a single physical 1 Gbps network port. The network connections are configured via /etc/network/interfaces like this: auto lo iface lo ...
Mikko Rantalainen's user avatar
1 vote
1 answer
877 views

How can I easily (e.g. as easy as rsync or SCP) do a high speed (1gpbs) file transfer over an Internet-latency link?

A few times per year, I need to transfer massive files (20+GBs) over the Internet (latency 20-100ms), but with reasonably fast connections on the order of 1gbps between servers. Unfortunately, when I ...
john01dav's user avatar
  • 461
1 vote
4 answers
440 views

Bandwidth throttling software

I need to be able to simulate high bandwidth/high latency/high packet loss on my pc for the purpose of testing the software that I'm writing. I've seen some software that you can install on a ...
Steven Evers's user avatar
1 vote
2 answers
3k views

Should I enable "Intel NIC DMA Channels"?

I have HP DL360p Gen8 646902-xx1 I'm trying to optimize my config for low latency trading. Should I enable "Intel NIC DMA Channels"? Will that help/affect my system? From HP doc: Added a new ROM ...
Oleg Vazhnev's user avatar
0 votes
2 answers
1k views

syslog-ng: How to reduce high latency when forwarding logs to a syslog tcp consumer?

UPDATE 2: I've answered this via my new question at the link below. The root cause is behaviour by telegraf where by default it disconnects the TCP connection 5 seconds after the last received message....
davidA's user avatar
  • 393
0 votes
1 answer
5k views

Why my 2nd ip from traceroute is not answering the ping anymore? [closed]

My Internet is really laggy today, I did a tracerout and I realize that I'm having no answer from an ip at the beginning of the traceroute. see: Tracing route to 12.129.202.154 over a maximum of 30 ...
Pedro77's user avatar
  • 103