Questions tagged [bottleneck]

A bottleneck is the place where transmission is the slowest.

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Routing with an Allied Telesis switch and ARP bottleneck

I use an Allied Telesis x610/24-Ts switch as a central switch in a company building. The central switch connects several edge switches and also provides routing between VLANs. The forwarding ...
Jerry Xia's user avatar
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1 answer
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Unable to get my rsync of my software RAID 6 past 40MB/s. Looking for suggestions

Wondering what I could adjust to get my RAID 6 Software Raid to resync quicker. Currently it's proceeding at max of 64MB/s and averages to something around 25MB/s. Hoping to get it to 200MB: [...
DeliciousBoulder's user avatar
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Copying large file with robocopy during VMWare storage vmotion

if I copy massive files via robocopy during storage vmotion then is there any negative impact ? thanks,
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What could cause blocked requests in IIS?

I'm using IIS on Windows Server 2016 with MySQL and PHP on two almost identical servers. I've recently noticed a slowdown on one of my two servers but it happens only when my site tries to execute ...
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What could cause processes to not be active

Running linux and executing a bunch of PHP scripts. I noticed that our CPU usage was pretty low but many processes were sleeping, so started investigating. AWS EC2 with an S3 bucket. I can't seem to ...
D.Mill's user avatar
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Identifying saturated disks on CentOS 8

A quick background; I have a 10Gbit file server with six data SSDs running CentOS 8 and I'm struggling to saturate the line. Everything's fine if I cap bandwidth at 5 or 6Gbps. Here's some charts ...
Vimm's user avatar
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Strange behaviour of MySQL on Windows (CPU 100% with simple query)

We run MySQL 8 on Windows 2019 server (Dell R420, 32 cores, 64GB, SSDs on Raid10). Every now and then, our website goes completely offline, as the CPU on the MySQL server is completely bottlenecked (...
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sshfs - howto view load and find bottlenecks

I got 2 dirs mounted by sshfs from remove server. And suspect those make my app so slowly (app generate many i/o operations in this). I can use fdisk/iostat/iotop for diagnostic HDDs bottlenecks, but ...
Anton K.'s user avatar
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How do I know if SSD is the bottleneck in Linux?

I have a database server which uses a Samsung 840 pro disk. The load is constantly higher than usual, even if there is not much activity on the website. So I suspect the disk has worn out. But how can ...
Milkyway's user avatar
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Limitations to using many SSDs in computing server [closed]

This is a beginner's question: We have a powerful computing server for roughly 10 users which will be increasingly used for data processing. In the past the main bottleneck was I/O. I was wondering ...
Radio Controlled's user avatar
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How can I predict whether or not memory will bottleneck a CPU

My question is general, though I have a specific example. My question is this: How can I predict whether a powerful CPU will be fully exploited in a scenario with memory that is (relatively) low? My ...
MasterOfNone's user avatar
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How to determine the bottleneck of a given network

Consider an Access Point with a packet queue that can hold up to 50 packets and a network whose bottleneck is a link with a datarate of 50 Mbit/s. There are quite a few nodes connecting wirelessly ...
user503842's user avatar
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find bottleneck of a slow server centos [duplicate]

I have a virtual machine host running Centos 6. It is serving an android application with apache/php/mysql. When online users gets high in number , the server responds very slowly. Even ssh ...
BlackBrain's user avatar
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hardisk or network bottleneck?

Im trying to determine which hardware causing the bottleneck of the server, the server is mainly used for serving video files on a heavy traffic site. i have dstat output look like below (will get up ...
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What constant throughput and linear respone time tells about the system?

What does it mean when throughput in the system is constant and only response time changes (linearly)? Does it mean that I have to have a bottleneck?
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Is Quality of Service my ISP's responsibility? [closed]

One person on my network does a massive download, not caring too much about how long it takes. Someone else on my network doesn't want his incessant video streaming interrupted. My understanding is ...
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How to tune Nginx + MySQL + PHP-FPM bottleneck to resolve high server load?

My server, Ubuntu 14.04.4 LTS, is running at high load, currently running a single site with Nginx + Wordpress + W3 Total Cache + Memcached. I'm not sure if mysql is causing the workload issue. Here ...
KDX's user avatar
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How to find the bottleneck for slow rsync

I want to find the bottleneck for a slow rsync. I see these parts (on byte flow order): IO on source CPU on source Network CPU on destination IO on destination How can I debug this?
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Can a VLAN traffic affect other VLANS?

Consider 2 vlans VLAN-1 VLAN-2 VLAN-1 gets an abnormally large traffic spike from outside world. Will this affect the other VLAN and will the applications in VLAN-2 have packet loss and high ...
Arslan Mehboob's user avatar
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Bottleneck PHP/MySQL server

The server is getting slow on peak hours, and I don't really know how to find out the bottleneck. I can upgrade ram and cpu. Currently 2gb and 2x2.4ghz Linux CENTOS Around 60.000 pageviews per day ...
Server's user avatar
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Do routers and networks have have a “max threads” configuration? [closed]

I've been stress testing my application now and I've identified a high average network connection time. This is odd because I haven't gone over the max bandwith at all. What can this be caused by? ...
Sandeep Shan's user avatar
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1 answer
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MySQL high CPU usage on small website

I have a small website hosted on a dedicated server (FreeBSD 9.2, MySQL 5.6.1 and php 5.5.5). The problem is that MySQL eats a lot of cpu resources even if the website have a few visitors. The ...
Ivan's user avatar
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How to troubleshoot slow performance on AWS EC2/RDS?

We recently moved our web servers from some 10 year old boxes to AWS EC2. Usage of the site is currently higher now (it's our busy season) and the site has become much slower, which is unexpected ...
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Estimate if the network throughput is reached

I have 2 processes communicating over TCP/IP as following: process A sends 20 KB of data to process B and after some calculations process B sends the response (2KB) back to A. When I run both ...
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Does using all cores reduce efficiency?

I have a program (well, php script) which does some pretty heavy text searching - it loads a 2mb and 40mb file and searches through them to find where each word that appears in the first is present in ...
Benubird's user avatar
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Network card capable of capturing a tonne of packets and not dropping them?

Edit: Our server is trying to capture packets at between 500-600Mb/s, but is dropping packets 'due to kernel'. Data is being written to SSDs, and isn't bottleneck there. What things should I look ...
BIGMOOSE's user avatar
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1 answer
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How can I find the bottle neck? [duplicate]

I have a EC2 m1.large Ubuntu 13.04 Instance runs PHP 5.5, PHP-FPM and NGINX. Cache is handled by Elastic Cache using Redis and the database connects to a separate m1.large MongoDB server. The content ...
Jonathan Thurft's user avatar
8 votes
2 answers
5k views

Why is Postgres sitting 95% idle, with no file I/O?

I have a TileMill/PostGIS stack running on an 8 core Ubuntu 12.04 VM on an OpenStack cloud. It's a rebuild of a very similar system which was running nicely on very similar hardware (same cloud, but ...
Steve Bennett's user avatar
2 votes
1 answer
116 views

May a low DRAM router be a bottleneck for a LAN?

I need to install a LAN that is a hybrid between a star LAN and a cascade LAN. There are two levels (I mean that the maximum number of link to go from the central switch to the most external switch is ...
Ramy Al Zuhouri's user avatar
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4 answers
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Flush-0:n processes causing massive bottleneck

I have a LAMP cluster that shares files via NFS and occasionally one of them will be stricken for a while when mysterious flush processes start appearing. Can anyone help me? The only way to resolve ...
Tom's user avatar
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Linux I/O bottleneck with data-movers

I have a 24 core machine with 94.6GiB RAM running Ubuntu server 10.04. The box is experiencing high %iowait, unlike another server we have (4 cores) running the same types and amounts of processes. ...
Benjamin's user avatar
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1 answer
284 views

Server hard disk read speed and client download speed, is there a connection? [closed]

Ok so a client's download speed is only as fast as a server's upload speed, and vice versa. Based on the answers to this post: Does upload speed depend upon download speed of the server? In other ...
Mywiki Witwiki's user avatar
1 vote
0 answers
133 views

Good Perfmon Counters for Initial Troubleshooting

I increasingly deal with users who complain there "computer is slow" or that "it takes forever to load" on the laptops we provide (fairly standard build of Windows 7 32-bit with Office 2010 and a few ...
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3 votes
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Performance monitoring on Linux/Unix

I run a few Windows servers and (Debian and Ubuntu) Linux and AIX servers. I would like to continously monitor performance on these systems in order to easily identify bottlenecks as well as to have ...
ervingsb's user avatar
  • 395
2 votes
1 answer
632 views

Solaris/UNIX: Does snoop have the potential to slow down network traffic?

This is the way I see it. A copy of the network activity is written to a buffer, and snoop reads from the buffer. As long as snoop is able to get the data out fast enough (writing directly to a file ...
700 Software's user avatar
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1 vote
1 answer
524 views

Server freeze (Disk I/O possibly)

I have a Windows Server 2008 machine that is resyncing disks after a powerloss. The issue is that the system becomes unresponsive after about 10 minutes. We've checked with resource monitor and found ...
user avatar
1 vote
1 answer
2k views

Mysql hangs up the server. How to avoid this?

Sometimes my website 'goes down' due to Mysql consuming all the resources, but I think it does not stop creating more httpd processes. Is that possible? If I restart apache, these processes disappear ...
HappyDeveloper's user avatar
2 votes
2 answers
12k views

What iowait values are ok?

I am trying to find the bottleneck of a server running a fairly busy php/mysql site. My first culprit was io but iostat shows that on average iowait consumes only %3.60 of cpu time. here is the ...
alfish's user avatar
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Diagnosing the slow performance of my NAS?

I recently built a NAS box on top of ubuntu server. I have an average transfer of about 10mb/sec over gigabit wire to my computer. I was hoping you guys could give recommendations on how to pinpoint ...
Jess's user avatar
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2 votes
2 answers
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web app reaching emailing limits - what is the next step up?

Recently i have been working on a popular web app that currently has around 70k members and a lot of traffic, i migrated the site to a new extra large EC2 instance and it seems to be a massive ...
David's user avatar
  • 123
1 vote
2 answers
3k views

Should I use nginx exclusively, or have it as a proxy to Tomcat (performance related)?

I've planned to create a website that'll be pretty heavy on dynamic content, and want to know what would be the wisest choice for part of my webstack. Right now I'm trying to decide whether I should ...
Kevin's user avatar
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3 votes
1 answer
1k views

Tangible benefits of keeping web applications and web server separate?

We develop and maintain web applications; and in our current setup; we are using a three-tier system of database server, application server, and web server. So far, so good. The problem we are ...
Williham Totland's user avatar
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3 answers
517 views

Where to look for the bottleneck when download slows down?

Image downloading from our site slows down every evening. Compared to daytime we get %50 more traffic over the evening. In exact figures, during daytime hours, hourly pageview count is around 20k, ...
Haluk's user avatar
  • 963
5 votes
2 answers
5k views

Steps to diagnose performance bottlenecks on Mac OS X

If you wanted to track down performance issues on a machine running Mac OS X and find out what was causing slowdowns, which command-line or graphical tools would you use, and how would you use them? ...
Dave Cahill's user avatar
4 votes
3 answers
2k views

How to determine bottlenecks on Ubuntu LAMP environment

What kind of tests should I run to determine bottlenecks on my server? I'm trying to optimize so I can maintain heavy load spikes when they occur. I'm running Ubuntu in a LAMP environment.
Ben's user avatar
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1 vote
3 answers
505 views

Identifying the bottleneck

So I've got nginx and php-fpm on a cloud server. Using apache benchmark with these settings: ab -n 300 -c 5 http://example.com/ So the cloud server (from rackspace) was a 256mb one. I ran htop while ...
Matthew's user avatar
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1 vote
1 answer
504 views

How to Build a High Performance Network Traffic Recorder With no Bottlenecks (20Gbps)

I need to build a server which is capable of capturing 20 Gigabit/second network traffic (2 x 10g network adapters - 99% utilization) and store them on a disk with zero packet-lose. The requirements ...
Tzury Bar Yochay's user avatar
0 votes
1 answer
946 views

Looking for a bottleneck in MySQL server

I have two Ubuntu servers with very similar, if not identical, configuration: both have 16 cores (4 E5540 Xeons), 16GB RAM, HP Smart Array P212 controllers with 2 HDDs in RAID1. I/O scheduler used is ...
minaev's user avatar
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1 vote
2 answers
159 views

Hypervisor load on local disks

What is the I/O load on the local disk system for the host OS in XenServer? I can't find this info anywhere. As we have a SAN for the VMs themselves, can we get away with cheap controller / SATA disk ...
user avatar
2 votes
3 answers
3k views

Very slow harddisk performance

Today I was trying to execute a long-running (but highly optimized) query on a server in our company. I've run the same query on the same data on my home computer (5400rpm harddisk) and it took about ...
Wikser's user avatar
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