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Questions tagged [high-load]

All aspects of high-loaded systems development and maintenance.

All aspects of high-loaded systems development and maintenance: design, algorithms, architecture, technologies, development, testing, databases, storage, support, hardware, hosting, management.

219 questions
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How to tune TCP for high-frequency connections between two nodes

I've been scratching my head for the past few days, trying to come up with a solution for the following problem: In our data center we have a F5 running on BigIP hardware that acts as a single ingress point for HTTPS requests from client machines in…
Christoph
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4 answers

How to limit number of sessions?

I need a way to track and limit web sessions to a web app. A "session" is loosely defined as the single user browsing the pages of the said web app. I think it can be translated to: a session is defined as a tuple alternatively as…
the-wabbit
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1 answer

high load average, high wait, dmesg raid error messages (debian nfs server)

Debian 6 on HP proliant (2 CPU) with raid (2*1.5T RAID1 + 2*2T RAID1 joined RAID0 to make 3.5T) running mainly nfs & imapd (plus samba for windows share & local www for previewing web pages); with local ubuntu desktop client mounting $HOME, laptops…
John Stumbles
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2 answers

Is a 'high' IO rate healthy?

I do a lot of work with my Linode that currently hosts a site, but every now and then (usually once every two months or so) - I'll get a warning about my IO rate being too high (Usually just higher than 6000). The last one I got said: "Your Linode…
user82250
7
votes
2 answers

Ubuntu load average spikes but CPUs are idle

We have a server on a cloud network, provided by a third party. We are running Ubuntu 10.04 Server Edition. The problem happens at seemingly random times, around one to three times a day. The load average in top usually sits around 2 and the server…
Travesty3
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2 answers

High system interrupt rate

My server has 24 CPU cores, 96G memory, installed CentOS 7.2 x86_64. After starting my program with a large data set, my program will use about 50G memory, and the Linux system will show a high rate of system interrupts, but context switching rate…
user416983
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1 answer

Is there a backend-aware load balancer for Rails/Passenger?

We have 3 Ruby on Rails applications (A, B and C) installed on a number of application servers. Our front end is HAProxy, backend is Apache + Phusion Passenger. Originally we had all 3 Rails apps installed on each application server, but this setup…
Alex Kaushovik
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2 answers

How to choose a correct value for open_file_cache in nginx configuration?

I have a website with load of about 60 000 requests per minute served by nginx. Recently, I have enabled the open file cache and saw a dramatic improvement in performance. But in the evenenings, when loads is maximum, response times are still quite…
Temnovit
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100% CPU load on Ubuntu 10.04.3 LTS 64bit

I have trying to fix this issue for two days with no success. The server is a MySQL database server. Hardware: DELL Poweredge 1950, 2x Intel Xeon Quad Core E5345 @ 2.33GHz, 16 Gb mem, 2x 146Gb SAS (software RAID1) Software: Ubuntu 10.04.3 LTS,…
deadtired
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3 answers

Filesystem performance tuning options for ext3

I have a brand new server w/48G RAM which I am going to use as a DB server. I don't expect problems with disk reads, but I definitely would like to optimize for write intensive load patterns. The OS is RHEL 5.6 and the FS is ext3, I've added…
Alex
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2 answers

Fast pinging without requiring the response

I am trying to measure one way latency between two machines and I would like to use ping to send ICMP packets from one machine to another. The interval between the packets should be 1 micro second (1us) and I want to sent 1 million packets (10^6),…
Grey
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How does a typical http(s) load balancer work?

I know that there are some situations that we encounter heavy http(s) load on a server and we should use a load balancer to distribute load among several back-end servers. But I've a confusion here! Lets suppose that too many users (lets say…
Ehsan Khodarahmi
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3 answers

High CPU usage without useful information from top command

Over the past 2 days I started having problems with a server which has a few users on it. The server is an OpenVZ VPS. Normally when I experience high CPU usage, I always use top command to find out the reason. But for this server, I don't receive…
aye
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1 answer

High load average due to high system cpu load (%sys)

We have server with high traffic website. Recently we moved from 2 x 4 core server (8 cores in /proc/cpuinfo), 32 GB RAM, running CentOS 5.x, to 2 x 4 core server (16 cores in /proc/cpuinfo), 32 GB RAM, running CentOS 6.3 Server running nginx as a…
Nick
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2 answers

Uneven CPU core utilization

tl;dr: First CPU core is consistently saturated, all other cores are consistently under-loaded. A VM, inside Ubuntu-based Xen XCP: $ uname -a Linux MYHOST 2.6.38-15-virtual #59-Ubuntu SMP Fri Apr 27 16:40:18 UTC 2012 i686 i686 i386 GNU/Linux $…
Alexander Gladysh
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