Performance tuning is the process of modifying a system to improve its efficiency. This is also known as optimizing.

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Webserver: Performance impact when storing session files on /dev/shm

I have a website runing on a typical setup: Linux, Apache, PHP, MySQL. However, what's not typical about it, is that it's getting tons of traffic (400,000+ visits a day) and so, efficiency is becoming ...
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390 views

DB2 insert performance - How to measure

[From stackoverflow] Im trying to find a way to speedup my inserts to a DB2 9.7.1 (ubuntu linux) Im watching vmstat and trying to gather some statistics via the db2 get snapshot commands but im not ...
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133 views

increase nginx active connection more than 65535

currently I'm doing setup for nginx to accept C1M, I do in my Virtual BOX with Centos 7.0 and RAM 10G. Here my sysctl.conf configuration. fs.file-max = 9999999 fs.nr_open ...
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673 views

Linux : SSD performance tweaking queue

I've allready applied well known mountpoint options for ssd, enabled stuff in LVM for ssd optimisation as well. Now i've ran into a possible challenge. Would it be possible to gather information on ...
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590 views

rmem_max more than rmem_default

I just installed centos 6.3 freshly and noticed the following: [root@localhost user1]# cat /etc/redhat-release CentOS release 6.3 (Final) [root@localhost user1]# [root@localhost user1]# cat ...
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One Slower/Larger VS Two Faster/Smaller RAM [closed]

Generally speaking, performance-wise, which one is the best (putting brands aside)? 1x 8GB 1333MHz RAM or 2x 4GB 2400MHz RAM Both DDR3.
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LAMP -> CPU usage of Apache processes too high

I have a LAMP system with CentOS 6.4, Apache 2.2.15, MySQL 5.5.32 and PHP 5.3.26 with APC 3.1.10 using a Drupal CMS (https) on a virtual machine with 4 CPUs and 6 GB RAM. My problem is the CPU usage ...
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173 views

How do I go about finding the bottleneck in a slow web based chat application

I am working on a one-to-one chat application running in production. It uses StropheJS to connect to Ejabberd server over BOSH (using ejabberd's default connection manager). The main problem we are ...
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535 views

Varnish: Exclude section of page

Is there any way to exclude some webpage parts from cache? For example, I have Recent Additions block on my homepage which gets refreshed after every 15mins. I know there is something like ESI ...
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393 views

High response time with pingdom

I have a server hosted at my end, I am monitoring the server with pingdom and also my router. Strange thing is the response time towards the router is fine, but when the traffic flows towards the ...
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170 views

Adding varnish and memcached to an running single server web site

Current set up; I have a single dedicated server running a web site (it's a lamp stack forum) OS : CentOS CPU : Dual 3.2Ghz Quad-core Xeons RAM : 40GBs (10x4GB DIMMs) Storage : Software RAID1 with ...
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231 views

503 error Varnish cache when eAccelerator is started

I have a Magento installation running on x-large Amazon server. I have Varnish, memcached and eAccelerator installed on the server. At first everything was working fine, but then at some point it ...
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663 views

Perfmon - Redirector current command 0 result

I'd like to monitor how many SMB connections there are at any given time for my 2008R2 file server, but when I add Redirector/Current Commands in perfmon, I get 0 results. This KB from Microsoft isn't ...
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86 views

Server stops responding without any load, restart required

Sever is working as a very high-traffic application back-end We are using Apache2, MySql, and PHP. We have already optimized the above for best performance Server configuration is: Linux ...
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273 views

adding new scheduling policy to the kernel

i'm working on a redhat 8 linux and i want to add new policy for scheduling the processes , could you help me with : 1) where to define the new policy 2) how does the process of assigning a policy for ...
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917 views

Oracle Application Server Performance Monitoring and Tuning (CPU load high)

Oracle Application Server Performance Monitoring and Tuning (CPU load high) i have just hired by a company and my boss give me a performance issue to solve as soon as possible. I don't have any ...
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759 views

Increase bandwidth of Linksys WRT54GL (with Tomato inside)

I have Linksys WRT54GL with Tomato firmware installed. When I connect internet cable directly to a computer I can download at about 8 MB/s, however when internet is access through the router maximum ...
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2k views

How to check for bottlenecks in Windows Server 2008 R2

I recently switched out a 10 year old server for a brand new server in a small office and upgraded from Windows Server 2000 to Windows Server 2008 R2. After the switch was complete and some ...
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1k views

How to speed up apache

We have a server with 8Cores, 16GB of RAM and RAID 0 SAS 10K drives. Our goal is to use this to serve a fairly simple php application quickly. We have tested all other components and we think we have ...
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887 views

IIS6 - Classic ASP - “out of memory”/“out of string space”

We have a classic ASP application that's under significantly more load than usual. We are from time to time been getting "out of memory" and "out of string space" in the httperr. We do not usually ...
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882 views

MySQL Memory usage

Our MySQL server seems to be using a lot of memory. I've tried looking for slow queries and queries with no index and have halved the peak CPU usage and Apache memory usage but the MySQL memory stays ...
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2k views

Very low performance of raid6

I noticed that writing to raid-6 is very low, but when I make tests with hdparm the speed is reasonable: dd if=/dev/zero of=/store/01/test.tmp bs=1M count=10000 Gives: 50Mb/s or even less. The ...
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3k views

What is bottleneck of my Apache server?

$netstat -anp | grep :80 | grep TIME_WAIT | wc -l 840 $netstat -anp |grep :80 | grep ESTABLISHED | wc -l 50 memory usage : 850MB / 1000MB apache2.conf contains.. <IfModule ...
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46 views

Why did my newly added index show up as a 'statistic'?

We are attempting to tune our SQL Server 2005 database as we frankly have no indexing on our tables and our CPU usage is starting to max out at 100%. We have ran SQL Server profiler for a 3 hour ...
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5k views

How to see actual size of tcp send and receive buffers?

we are on a debian system and are trying to tune the tcp/ip stack to our needs. We all know that you can set the maximum tcp buffer size with some kernel parameters like this: net.ipv4.tcp_wmem = ...
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1k views

Webalizer causing high CPU load

We use webalizer to generate reports on our Apache access logs - it is useful in conjunction with Google Analytics. The problem is that webalizer uses ALOT of CPU when running. If I run top I can see ...
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1k views

How to use oprofile to find the bottle-neck of our web server?

Updated: ================================================================ I finally found the reason with oprofile. It was because the routing cache of Symfony. We have lots of pages with different ...
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3answers
4k views

Oracle tuning optimizer index cost adj and optimizer index caching

What is the correct way to set the optimizer index cost adj parameter for Oracle. As a developer I have observed huge performance improvements as this parameter is lowered. Common queries are ...
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15 views

How to measure file access by process over time?

I would like to take a sampling of data / file access over the course of several hours or days in order to ascertain what processes (with their accompanying files) are consuming the most drive IO in ...
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42 views

How to diagnose Nginx bottlenecks at specific number of users

Firstly, I know this is a loaded question, but I hoping that you guys will be able to point me in the right direction.... We've got a number of nginx-fronted web heads which site behind an AWS ELB. ...
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15 views

How to ascertain where to effectively allocate server resources?

I have recently received an upgrade to one of my servers of a 256GB SSD drive (this is in addition to two other primary 1TB drives) and a memory upgrade bringing the server to 64GB from 32GB of RAM. ...
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129 views

BTRFS, sector alignment and Advance Format Disks

I want to set up a BTRFS RAID1 setup with two WD Red 4TB disks, which possess 4K sectors. Since I am keen to get it right the first time before copying data to it (yes it will be backed up), my ...
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34 views

Performance Monitor Single W3WP

How to set my counters in perfmon to track a single W3WP process?
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Slow Tableau server performance in a datacentre

I'm installing Tableau Server 8.3 in our hosted datacenter and experiencing strange behavior. When I run a workbook on my ( average) laptop (8GB, 4 cores, SSD) in Tableau client, it runs in about 10 ...
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716 views

Apache Worker MPM / PHP-FPM Tuning

I have a VPS running CentOS 6.5, Apache 2.2, PHP-FPM v5.4 and MySQL 5.5. I take advantage of APC and Memcache. The VPS has 8 cores and 8GB RAM. I'm running a medium volume site (15,000 users / day, ...
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Capacity planning of messenger server [duplicate]

This is regarding a messenger server being developed. This will have thousands of users connected and will be able exchange messages. Users will also be able to send messages intended for multiple ...
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46 views

Negative effects of setting nginx workers too high

I've seen numerous posts advising how to set nginx's worker_processes, but very few detailing what happens when this is set too high. I'm about to run some benchmarks, but I'd appreciate advice on ...
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95 views

How can i speed up an XWiki installation on debian?

We installed XWiki on Debian. Page load times in default config were about 2 seconds. Tuning the memory parameters according to the XWiki performanve guide brought it down to 1 second. But for a local ...
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279 views

Why is GlusterFS so slow here?

We've set up a mirroring pair of GlusterFS servers. No special tuning, whatever came "out of the box" with GlusterFS-3.5.1 in the official RHEL6 RPM, that's what we have. The cluster works, but the ...
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274 views

Tuning Apache KeepAlive Timeout for HTTPS

My website forces HTTPS everywhere and has an average first load time of 3-5 seconds. Thanks to caching, repeat load time is 0.8 seconds. The SSL negotiation takes 150-300ms on my server, so I want ...
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42 views

TOP processes by system time

I have a system running 2 processes - MySQL and Java I'm seeing 20-30% of the time spent in %system. I've looked around to try and find a way to identify which what the balance of the system time is ...
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81 views

Solr Query thread limit

While performing stress tests of our website, it looks like Solr could be bottleneck. It has enough ram, CPU usage is far from 100%, but we still facing problems of waiting for solr response for even ...
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169 views

Tunning nginx/php5-fpm : why low memory usage with 800 users?

I did optimize nginx with what I found on the internet My specs are 2 servers load balanced : Intel Xeon E5-1620v2 (4c/8t 3,7 GHz+/3,9 GHz+) 32 Go DDR3 ECC 1600MHz 3x 160Go SSD Intel DC S3500 SATA3 ...
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2answers
143 views

MySQL performance problems on particular vhosts

I have a dedicated server setup (8 cores, 16 GB of RAM), running Ubuntu 12.04 LTS with latest updates, and I am experiencing some performance problems related to MySQL. I have multiple vhosts active. ...
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1answer
42 views

How to alleviate high disk reads on server?

We are currently hosting a 3TB library of image galleries on our web server, all searchable by users. With about 400 active users at a certain time on the website, our disk reads are pushing 100% I/O ...
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134 views

Nginx+Tornado performance tuning?

I have written a Tornado based Server that makes readouts from files on disk available via http. The size of the readouts I am serving is either about 10kb or about 1MB. I have a server machine with ...
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143 views

The `iostat` Command Describes a Non-Existent Block Device

The System An instance running on Amazon EC2 It is an m1.large EC2 instance The instance is running Ubuntu Server 12.04 LTS Here's What Happens... I wanted to measure disk IOPS on my system, and ...
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186 views

Lots of packets pruned from receive queue because of socket buffer overrun - reason to worry?

I know this question has been asked before, but maybe not in this particular context: I have a setup with a couple of MS2008R2 HyperVisor servers running a number of Ubuntu guests. Our webproxy runs ...
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172 views

how to disable all caches types in mysql server in order to do performance testing for my queries

I'm using Mysql Server 5.6.15 and i have a huge database with many complex queries. it seems that when I run the query the first time it takes X amount of time. when I execute it again it takes ...
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107 views

What's the bottle neck of server hit 100K request?

The following are two graph of my digital ocean vps instance handle load test request. 10K/s, The only different is the request file size, first is 10K, the second is 20K. Can any one point out the ...