Server Fault Stack Exchange
Server Fault Stack Exchange

Questions tagged [latency]

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

Latency is the time period between a signal being sent and a signal being received. In computer networking this can be the time between a sending of a packet and receiving of a packet.

To illustrate we can use the ping command:

PING google.be (173.194.66.94) 56(84) bytes of data.
64 bytes from google.be (173.194.66.94): icmp_req=1 ttl=47 time=76.6 ms
64 bytes from google.be (173.194.66.94): icmp_req=2 ttl=47 time=74.8 ms
64 bytes from google.be (173.194.66.94): icmp_req=3 ttl=47 time=79.6 ms

The latency here is 76.6 ms.

329 questions
2
votes
1 answer

SSHD, NTPD slow to respond

My server has been responding very slowly ever since I put it into production, however it's not slow how you might think. When I SSH to the physical virtualization server I receive the typical login as: prompt. When I type my UN in, it takes and…
Alex Manley
  • 121
  • 11
2
votes
0 answers

How to measure latency using wireshark

I'm trying to measure the wire-to-wire latency of a blackbox application. The application engages in tcp offloading (kernel bypass), it consumes incoming UDP packets via a NIC and in response, publishes outgoing TCP packets via the same NIC. What…
user2635088
  • 121
  • 3
2
votes
0 answers

Tradeoffs between cross-cloud and cross-AZ-single-cloud deployments

We have a educational system (federated microservices that are running mostly on AWS EC2, RDS MySQL and a message queue) that is already distributed across regions, primarily for latency hiding, though it has been useful for failovers. We're now…
Jedi
  • 458
  • 1
  • 5
  • 20
2
votes
1 answer

TCP retransmission delays - lost acks

Maybe somebody will be able to help me out with this. I'm trying to find out if there is anything that can be optimized server-side to reduce delays in case of packet loss. Environment: Windows 2012 client, CentOS 6.x server [Couchbase], same…
PP_2
  • 21
  • 2
2
votes
2 answers

Should I be concerned about my iSCSI SAN traffic?

I have a meeting with DELL today to discuss some of our SAN setup and I want to be able to talk about what I am seeing. We have an average Latency of 20ms. I'm attaching a screenshot of what it is currently showing over an extended time range. If…
jasoncrider
  • 134
  • 2
  • 13
2
votes
1 answer

How to debug linux latency issues under network load

I have 12 mixed Ubuntu 12/14 database Cassandra nodes. All nodes are baremetal nodes with SSDs, 1Gb network cards and are all colocated in the same DC (managed colo). Under light operation, the latency between all the nodes and our cloud nodes (in…
killachaos
  • 135
  • 4
2
votes
0 answers

Azure Web App Latency

I have a simple Azure Web App setup using a single Standard Small Instance type in Central US region. The site itself is running a node.js website. I noticed google crawl was reporting average latency around .5s. To monitor I added a 6 Azure…
Element
  • 856
  • 2
  • 10
  • 14
2
votes
1 answer

Windows 2012 Shared Drives Odd Latency Issue

I have a Dell T110 II running ESXi 5.5 with a Windows 2012 R2 instance running with the following roles: ADDS DHCP DNS File/Storage Svcs WSUS I have two shared folders -- Scans and Data -- which are mapped via logon script: net use B:…
Brandon Wetter
  • 221
  • 2
  • 5
2
votes
1 answer

SSH Client sporadically hangs for few seconds

On Ubuntu 14.04 LTS when I use SSH client, it hangs sporadically for few seconds every minute or so. no input is lost is just delayed. SSH -V OpenSSH_6.6.1p1 Ubuntu-2ubuntu2, OpenSSL 1.0.1f 6 Jan 2014 .ssh/config Host * ServerAliveInterval…
Nabil Sham
  • 267
  • 1
  • 2
  • 9
2
votes
2 answers

How much overhead does the Chinese firewall add to a network conversation?

Does anyone have any stats on this? I'm mainly asking from a private network perspective (assuming that they are affected by the firewall as well). That is, all of my apps that are in use in China are on our internal network. I got to thinking…
squillman
  • 37,883
  • 12
  • 92
  • 146
2
votes
1 answer

ELB - High latency when enabling cross-zone balancing

I'm working on improve our infrastructure reliability in AWS and one of my tasks is enabling cross-zone balancing on our ELBs. Our ELBs receives around 20K request by second on rush hours as well as all our instances are in us-east-1d. I've…
Jose Peinado
  • 35
  • 4
2
votes
2 answers

SMB Latency Issue with Multiple Users

We have a program that works by being shared over the network as a normal Windows Mapped Drive. You run the program from the mapped drive and it stores its files in flat file databases in that mapped drive and everything is supposed to work fine. In…
Mark Murfin
  • 121
  • 3
2
votes
0 answers

upstream timed out (110: Connection timed out) while connecting to upstream

I have my backend in France and one of my frontend servers is in Japan. This issue doesn't happen with any other of my frontends, only this Japan server, which already has about 2s latency from most locations. The latency isn't what's bothering me,…
Derek
  • 21
  • 1
  • 2
2
votes
2 answers

SMB2 over 1GB PTP Link - 10ms latency

Maybe I'm expecting way more from SMB2 than what's realistic. Here is the scenario. Windows 7 Client (Local) A) Win2008R2 Server (LAN -- 1GB, <1ms) B) Win2008R2 Server (WAN -- 1GB, 10ms) (Identical server hardware) Scenario 1: I have a single…
breckit
  • 43
  • 1
  • 4
2
votes
2 answers

Configuring Squid to choose a peer cache based on latency to destination website?

Is there any way to configure Squid to choose a peer cache based on the latency in communication to the http port on the destination webserver? For example, let's say we have two Squid caches - server 'A' in the USA and server 'B' in China. We know…
Mjollnir
1 2 3
…
21 22