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

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ESXi very slow with WD reds

I have a small company and we offer tech support to small companies. I've been using the HP Gen8 MicroServer in most of them as a replacement of homebuilt computers for some time. Sometimes customers ...
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101 views

MySQL taking too much CPU

Below is my .cnf file and if I see my CPU consumption 99.99% of it my the mysqld commands. The MySQL server is connected from remote machines that update data in it frequently, but I make sure that ...
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88 views

How To Tune Apache on Ubuntu 14.04 Server

Currently on my Apache 2 (Apache 2.4.7 to be exact) on Ubuntu 14.04, I have this setting: /etc/apache2/mods-enabled/mpm_prefork.conf <IfModule mpm_prefork_module> StartServers ...
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123 views

What do users see when Apache reaches MaxClients?

Occasionally, in my Apache error log, I will find: [error] server reached MaxClients setting, consider raising the MaxClients setting I've purposely lowered MaxClients in the past (to 60) due to ...
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30 views

Does Apache mod_status give any insight to tuning Apache config?

Does the Apache mod_status output give any insight to tuning Apache prefork config? For example, using Apache's mod_status, I figured out that My server gets 3 requests/sec average, the range is ...
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47 views

NFS performs ways worse than SSHFS, how can I debug?

Situation: zfs server over 10GbE p2p at 192.168.201.1 running omnios, debian client at 192.168.201.2. The nfs performs fairly well on big files but horribly slow on small ones. For instance, cp -r ...
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53 views

nginx can't execute many requests

I have a question about nginx tune. I have an application which I want execute 200 times every second. I created bash file and used wget with bqO switch for execute. But it has a problem. When the ...
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22 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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46 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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149 views

Configure HAProxy on Linux to accept 10K simultaneous connections

I have HAProxy 1.5 running on Ubuntu 14.04 (modified). It accepts connections on http and https ports. Two backend applications process requests using persistent connection. When I create around 2200 ...
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17 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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45 views

Performance issues with cross-drive NTFS junctions

I have the following setup: Windows 8.1 32-bit Drive 0: system drive, SSD, NTFS, mounted at C:\ Drive 1: data drive, magnetic HDD, NTFS, mounted at C:\Users\Database User\Documents and Z:\ ...
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57 views

Seeking advice on performance metrics based on NewRelic dashboard

Some background: I have been given access to our newrelic dashboard for the production servers running a django app on an AWS account, and tasked to come up with some gatling.io (performance testing ...
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75 views

measuring network throughput with netperf

I'm doing benchmark test of Linux server using netperf. According to information at networksecuritytoolkit the theoretical max throughput rate for 1514-bytes packets is 117.35 Mbp/s. However I'm ...
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168 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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708 views

Slow performance due to txg_sync for ZFS 0.6.3 on Ubuntu 14.04

I am using native ZFS with "ZFS on Linux" installed from the PPA here. Setup was not a problem and I am using it in mirrored configuration with two WD 4TB Red HDDs. Unfortunately I am having ...
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1answer
107 views

Data Transfer Speed Hardware Config

First off, I am sorry if this gets a little scattered, it encompasses a large problem for me I have been dealing with for some time. Here is a little background: I operate an educational website ...
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37 views

Performance Monitor Single W3WP

How to set my counters in perfmon to track a single W3WP process?
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98 views

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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118 views

Tuning Linux TCP for large number of TIME_WAIT

It looks like we have a bunch of tcp connections hanging around on a busy webserver, this is the output from ss -s: Total: 366 (kernel 1037) TCP: 72108 (estab 130, closed 71964, orphaned 0, synrecv ...
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940 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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1answer
88 views

Will noatime on a tmpfs volume improve performance?

I am using /run/shm/myfolder for nginx micro caching, also keeping ngx_pagespeed files there. I am wondering if there will be a speed increase if I go from relatime to noatime? It's for HDD, but on a ...
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28 views

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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511 views

Apache Start Servers, Min/Max Spare Servers Ram Consumption Influence

I have a 1gb ram VPS. If I stop apache I have 400 mb ram free. So the max clients should be (total ram - used ram) / max_service_ram_consumption = 400 / 31. So MaxClients should be 13. These are the ...
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53 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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114 views

Running “find” command generates high load

I run this command on a Debian server with SSD drives configured as RAID 1: ionice -c 3 find . -type f -amin -1440 -mmin +1441 -not -path custom/ -print0 on a path which contains over 1.7M files and ...
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96 views

How to tune a web server and prep it for lots simultaneous visitors?

I have another related question but I'm deviating from it since I'm changing my server to use nginx instead of Apache. Related: Server problems, running out of RAM, really high load average I'm ...
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144 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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325 views

Server problems, running out of RAM, really high load average

I desperately need help in figuring out how to troubleshoot this problem I'm having. I run a fairly mission critical web server (Debian 7.5, 512MB RAM, 512MB swap, Apache, MySQL). It runs a couple ...
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120 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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321 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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326 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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651 views

difference between taskset and cpuset

I'm trying to reduce the latency of my linux network application. I've learned that there are two tools for "binding" a program to particular CPU core: taskset and cpuset. Which one should I prefer? ...
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43 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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101 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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3k views

Low latency TCP settings on Ubuntu

There is a server for measurements running on Ubuntu in my lab . And there is C program, which receives data through TCP connection and should as soon as possible send a reply. Network latency when ...
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190 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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1k views

Optimize Apache for EC2 micro instance

I'm running apache2 on a EC2 micro instance with ~600 mb RAM. The instance was running for almost a year without problems, but in the last weeks it just keeps crashing, because the server reached ...
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225 views

Centos Server Recently slowed down significantly

I have Dedicated Server on 1and1 with RAM - 16 GB HD 1000GB CPU: Intel(R) Xeon(R) CPU E3-1270 v3 @ 3.50GHz, 4 cores Centos 6 Apache/2.2.15 PHP 5.3.3 Mysql I have a video sharing website (on ...
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152 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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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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138 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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54 views

What is the correct way to track and monitor Exchange DB replication “pressure” over time?

I want to determine if some databases are overloaded or unbalanced, and think that looking at the transaction logs created per database over time would tell me which DB is at risk of missing RPO ...
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60 views

Multipath tcp application level performance measurement

I am working on a project related to Multipath tcp and I want to measure the goodput and the RTT at the application level. I don't want to use a traditional tool(netperf, iperf, ...) and I want to ...
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1answer
221 views

Execute ps1 script when CPU threshold is meet

I'm looking for a function similar to Debug Diagnostics Collector. Where you can setup a performance (or any counter) trigger (eg. above 50% CPU over 50 seconds). Once condition of a trigger are ...
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156 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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178 views

4096 and 8192 block size read slower than write? by using lsi 9361-8i RAID10

is it possible that 1024 and 2048 block size read speed is faster than 4096 and 8192 block? I'm using lsi 9361-8i with RAID 10 , with 8 x Kingston E50 250G. result: 1024 = Write: 2,251 MB/s ...
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1k views

NFS Over OpenVPN: Top Performance Boosters

I have two VPS's - One is running 2008 Server R2 and the other is a Ubuntu 12.04 installation. I am using the Windows VPS for RD sessions for Quickbooks and a couple other apps and using the Ubuntu ...
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66 views

IRQ not handled by all CPUs

I have a problem about balancing irq. I took irq numbers from /etc/interrupts and assigned each irq to each of 24 CPUs as this tutorial says for i in {143..166};do cat /proc/irq/${i}/smp_affinity; ...
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174 views

famd/gamin timeout issue with courier-imap

I'm running a mail server for about 200 users with courier-imap on Debian 7. This server is running a linux kernel 2.6.38 inside a Xen guest having 2 cpu cores and 2 GB RAM. The server accept ...