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

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Can VPNs reduce latency? [duplicate]

I've found a common subject in forums asking about using VPNs to reduce latencies between the gamers and the game servers. I've even found some blog posts confirming this. From my understanding, ...
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3answers
435 views

How to compare RDP latency?

For a remote Windows desktop solution, accessed from Las Palmas de Gran Canaria, I want to evaluate various options. What currently comes into my mind: EC2, Ireland Azure Virtual Machine, Ireland ...
0
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2answers
248 views

Why my server request takes 28 Second to get response?

I have a Wordpress website on a Godaddy server having at http://kerala.letmeshare.org. When I request to get this website this takes almost 28 sec to get reply. Because of this I made a complete ...
0
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1answer
274 views

Extremely high apache 2 initial response time, no system load

I've noticed recently that a VPS that I administrate has some strange Apache behaviour. Essentially, any HTTP request hangs for about a second before it is actually served. Output from ab shows ...
0
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2answers
249 views

Raid 1 and Latency

I am aware that RAID comes with certain write penalties, etc and that varies at different levels. I am trying to figure out how latency is affected in RAID 1. From my SAN, I can look at the number of ...
1
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1answer
294 views

What could this extra 50ms latency be on my unbound DNS resolving server (Fedora)?

I have a discrepancy in query latency. It's not a problem, it's just strange enough to worry me. Client machine (Fedora 18) runs unbound-1.4.19-1.fc18.x86_64. Server machine (Debian 7 testing) runs ...
0
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1answer
149 views

How do I calculate the ethernet NIC-to-NIC time to send a MTU packet (1500 bytes)? (OS-excluded) [closed]

I understand it will depend on the speed of the ethernet 10 Mbit to 100 Gbit. Given an ethernet speed, how do I calculate the time spend in the wire from NIC-to-NIC? I am assuming here that the ...
1
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1answer
332 views

Exchange Database Write Latency and ActiveSync - correlation?

We have an increasing number of ActiveSync devices connecting to our Exchange 2010 infrastructure (one primary mailbox server with about 920 accounts and counting; plus a cas/hub in the primary site). ...
0
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1answer
56 views

Adjust drive latency/lag on Server 2008 server with an array?

Got a 2008 server in production , which currently has "one" disc. (Actually a SAS array, presented as a single disc to the OS.) This "disc" is partitioned into a few sections, with some free space ...
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0answers
204 views

Network latency in Ubuntu 12.04 LTS

Until recently, my internet connection on my Ubuntu machine was working fine. Then, seemingly out of nowhere, I'm finding severe latency problems. For instance, in my web browser, I'll attempt to ...
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1answer
306 views

What is a “Latency Outage”? [closed]

I'm one of many customers of Windstream, the only internet provider in my area, and just after having hit the 1-year mark of being a customer, my 10M internet connection became about a 512k ...
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1answer
286 views

Ultra Low Latency Linux Distribution or Kernel [closed]

I'd like to know if there are any linux distributions that are focused on low latency networking. The area I'm working in is algorithmic trading, and extremely low latency comms between machines is a ...
0
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1answer
259 views

Why do these ipfw delayed pipes have no effect?

I'm on OSX 10.7.5 and am attempting to add some latency to the connection to my personal domain with ipfw, using this article as a guide. Normal latency: > ping -c5 troutwine.us ...
0
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2answers
646 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 ...
3
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1answer
406 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, ...
1
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0answers
109 views

Website latency and bad tcp packets

I have multiple websites hosted on a Linode VPS and I'm having an issue with one of them: every page that I try to load has about 10 seconds latency. Apache logs are clean and the other websites on ...
0
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2answers
440 views

High latency issue for web service call from amazon aws ec2 to local server

We have a legacy web application that is running in our data center on premises located in Houston. We have a developed a new .net 4 based web application in order to provide new features to ...
4
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1answer
4k 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. ...
0
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1answer
210 views

What exactly is cut-through latency?

This switch datasheet specifies that the "cut-through latency" is 300ns. What exactly does "cut-through latency" mean? Is it: The difference in time between a packet's head entry and that packet's ...
7
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3answers
362 views

TCP Window Scaling for Satellite Connections

A satellite connection generally has a RTT around 500ms. Connections generally suffer sub-optimal transfer speeds, in spite of large amounts of bandwidth because TCP acknowledgements take too long to ...
5
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2answers
2k 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 ...
2
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2answers
178 views

Diagnosing network latency issues

I have two servers both with gigabit network cards that were experiencing severe latency issues communicating with one another. The culprit eventually turned out to be that one of the servers was ...
2
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1answer
106 views

Performance issue in using Amazon S3 for run-time updates

I have a web application hosted in Amazon EC2 as well as in Rackspace. Users can upload files through this application and also modify them. Those files are stored in local storage in each of these ...
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0answers
714 views

Cisco AnyConnect VPN latency issues--how to diagnose/resolve?

Context: Our company has several remote workers. One of them is a fair ways away (1500 miles). All of the remote workers have Windows workstations and connect via the Cisco AnyConnect VPN system, ...
0
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3answers
143 views

Is this a latency issue or something else?

I have what I think may be a latency problem. I have a magento installation on a shared host. I know it's best to run magento on a dedicated server but it's early days and it's a good host. When I ...
0
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1answer
214 views

Latency and bandwidth limitation(WAN Emulation)

I have a requirement to emulate the impact of a new application on the WAN. The WAN bottleneck is a 65MB dedicated pipe between Australia and the UK. I have a setup to generate the traffic, but to ...
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2answers
96 views

Impact of Traffic through the first NIC on the second NIC

I have two NICs on a RHEL 6 server. They are both set at 1GB/sec full duplex. The first NIC has lots of small (< 100 byte) TCP socket writes. The second NIC is used to receive a 50 MB/sec TCP input ...
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0answers
25 views

Impact of Traffic through the first NIC on the second NIC

I have two NICs on a RHEL 6 server. They are both set at 1GB/sec full duplex. The first NIC has lots of small (< 100 byte) TCP socket writes. The second NIC is used to receive a 50 MB/sec TCP input ...
2
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2answers
250 views

Cross-cloud deployment: Servers on azure - Mongodb at MongoHQ (AWS) - known pitfalls?

Looking to deploy an existing Mongodb-backed solution to the cloud for a client. I'm hoping to combine MongoHQ and Azure to use the simplest possible Mongodb deployment together with the simplest ...
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2answers
760 views

Does a 150ms latency is good enough to launch a product (USA hosted in Europe)? [duplicate]

Possible Duplicate: Can you help me with my capacity planning? Having worked for weeks on a new mobile app product, we are finally preparing a public launch in the coming weeks. However we ...
0
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1answer
285 views

How to reduce DNS server latency?

Which is the best practise to reduce DNS latency? I'm using the beautiful powerdns DNS server, and i would like to lower down latency between internet client requests and the DNS server response. I ...
0
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1answer
410 views

Why is the latency on one LVM volume consistently higher?

I've got a server with LVM over RAID1. One of the volumes has a consistently higher IO latency (as measured by the diskstats_latency munin plugin) than the other volumes from the same group. As you ...
3
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2answers
808 views

LatencyTop on Centos 6.2

What do I need to do to get LatencyTop working on Centos 6.2? Does it involve compiling a debug kernel with some extra flags? Both the man page and the website are very short of information. ...
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2answers
82 views

I need to test the ballpark connection latency between two states - Any sites or easy ways to do this?

I am in Kansas I need to test latency to Oregon. Assuming I don't know anyone in Oregeon or know what hosts are pingable and also in oregeon is there any handy tool for this? It would be even better ...
2
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3answers
587 views

Tool to test MySQL latency [closed]

I want to compare the latency of my web application against two different MySQL servers: one a local machine and one hosted via Amazon RDS. What would be a good, free, and (preferably) easy tool to ...
5
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1answer
256 views

Hardware/topology recommendations for low latency UDP network

I'm setting up a LAN comprised of 60 end nodes that are receiving a high volume of UPD datagrams from one master server. The server sends 60 unique datagrams every 100ms, each datagram is 64 bytes. ...
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3answers
775 views

Geographic testing for latency

Really struggling to find tools that report latency loading a website from multiple geo-graphic locations. Are there such tools? I have begun replicating infrastructure in other EC2 regions, but find ...
3
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2answers
562 views

Cisco ASA Latency

What is the typical latency added when using a Cisco firewall such as ASA 5505? Are we talking less than 50 microseconds?
10
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4answers
4k views

Why do mobile networks have high latencies? How can they be reduced?

I'm increasingly seeing mobile networking technologies being used to get internet access in areas where it is otherwise not available. While mobile networking is usually not yet viable as the primary ...
0
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2answers
177 views

DSL :: Connection top speed is ok, but acceleration is low

My 2048 Kb/S ADSL connection downloads at the expected download speed 220 KB/s , but it takes too long to get to that speed, in other words the top speed is fine but the acceleration is terrible. This ...
0
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1answer
80 views

Why would reducing capacity under load improve latency on a server?

In this talk at Berkeley, Jeff Dean's slides contain the following note, about a third of the way through the presentation: Non-intuitive: remove capacity under load to improve latency (?!) The ...
0
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2answers
2k views

Need help troubleshooting highly variable ping times

I'm at work using Citrix (think Remote Desktop) to connect to client sites. With my job I have to write a fair bit of code while I'm connected remotely via Citrix, so the latency of my internet ...
1
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2answers
688 views

Is it bad that latency for our internal LAN varies greatly within the 15 - 40 ms range?

I've always thought the "typical" latency for a small office wired Ethernet network would be <5 ms. However, pinging the default gateway yields an average of 14 ms, and any host is around 30 ms. ...
5
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1answer
1k views

Esxi with iSCSI SAN slows down with many multiple VMs running

I have a server with ESXi 5 and iSCSI attached network storage(4x1Tb Raid-Z on freenas). Those two machines are connected to each other with Gigabit ethernet, and a procurve switch in between. After ...
11
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3answers
1k views

Determining a realistic measure of requests per second for a web server

I'm setting up a nginx stack and optimizing the configuration before going live. Running ab to stress test the machine, I was disappointed to see things topping out at 150 requests per second with a ...
4
votes
1answer
319 views

Combining Heroku with custom external services (e. g. Varnish or Postgres on EC2)

I'm planning to set up a Django site on Heroku. It will run on Heroku's Cedar stack, which allows Python apps, but doesn't include or support HTTP upstream caching with Varnish like the other stacks ...
4
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2answers
449 views

How to find the lowest latency midpoint between two geographic locations?

I'm looking for a geographic location (not service) to host internet services that will give me the lowest latency on connections from two other locations. How would I best determine the most ideal ...
4
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1answer
668 views

Hyper-V guests: intermittent latency

I am seeing latency on a Hyper-V host and its guests lately. When I run ping -f from a Linux prompt, I see the dots "pulsate" like a heartbeat indicating 2 successive latency spikes within 1 second ...
0
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0answers
188 views

SMB/CIFS shares and file-creation latency

I have web application that accepts an uploaded file, writes it to a share, and then sends a message to the middle tier with the name of the file for processing. There have been sporadic errors in ...
4
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4answers
3k 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 ...