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

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How to raise max no of file descriptors for daemons running on Debian Jessie?

I'm playing with pgBouncer as a connection pooling system for PostgreSQL. My system is a 12-core with 64GB RAM and 1Gbps network interface running Debian 8.1. Now I want to raise the limit for open ...
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14 views

How do force ixgbe to pass all packet ? Not good packets only? [on hold]

I m running freebsd 10.0 with ixgbe driver . But there is difference between total rec packets and good packets. dev.ix.1.mac_stats.total_pkts_rcvd: 699587190 dev.ix.1.mac_stats.good_pkts_rcvd: ...
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249 views

How do I tell how close I'm getting to somaxconn?

The sysctl option net.core.somaxconn defaults to 128 (on our systems) but can be raised. What exactly is this limit measuring and capping? How do I find out how close I am to the limit? Context: I ...
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40 views

Nginx performance when running multiple instances on the same machine

I'm trying to understand the performance impact of having multiple nginx instances (masters) running on the same machine, rather than having them all load into a single instance using different server ...
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1answer
33 views

Does 'tuned' need to keep running?

On my CentOS 7 systems, I use tuned-adm to set a profile appropriate to the environment during configuration, but after that, I never subsequently change that profile. It seems that the tuned system ...
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8 views

How to identify underutilized servers? [duplicate]

How to identify if the servers are underutilized and CPU/RAM resources can be decreased? Servers are virtual running on VMware. I thought of MAP Toolkit for collecting performance data and then ...
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1answer
39 views

Bind9 recursive queries have intermittent very long response times

I'm running BIND 9.8.1-P1 caching server on Ubuntu 12.04 LTS on kernel 3.2.0-86-generic-pae. I've been banging my head against the wall trying to figure this out for weeks and I just have no idea ...
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31 views

Investigating Citrix app server “slowless”

Currently have a client stating that the 5 users on a 2cpu, 4gb mem app server are experiencing slowness and often, locking up for moments at a clip. Framework is a VM running in vSphere 5.5 [intel ...
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24 views

How to track down bad performance on an api-server

If my api-server shows bad performance, such as high cpu - can this be blamed on the service or on the server? If a regular app-server shows bad performance, all I can do is track down the methods ...
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13 views

Maximum Network throughput for SWIFT storage

I have a SWIFT cluster deployed as part of Openstack which is currently giving me a max throughput of 95 MBS(Megabytes per second). There are 6 proxy servers and 6 storage nodes with replication ...
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74 views

Advice Tuning my server

as many others I Learn many info from you in the past and now I manage to run server independently , now I am new to sql tuning and I been searching around the web a while now and tuning seems to be a ...
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2answers
90 views

PHP5-FPM pm.max_children affect RAM or CPU+RAM?

Recently inherited a Nginx+PHP5-FPM server, and I'm learning and trying to optimize PHP5-FPM settings. Server info: 4 CPUs (8 threads) 7.5 GiB RAM PHP5-FPM info: pm.max_children = 5 ...
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2k views

Virtual machines and I/O heavy workload, is it ever sane?

I have seen on numerous virtualization services (Azure) and products (vmware,kvm,hyperv) I/O and system stalls under heavy I/O workload. My questions are: Is it ever sane to use a Virtualized ...
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1answer
74 views

How to resolve '[info] server seems busy' from apache server logs?

I've seen this question asked a few times but it hasn't had any real answer; so I've decided to post my resolution. The below info message can be seen in the apache error.log: [info] server seems ...
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1answer
28 views

Percona: What are the implications of changing repl.commit_order?

I'm currently doing some trials of Galera Cluster with Percona 5.6. I've progressed to testing a 2 node cluster on baremetal. With repl.commit_order set to 0 (off) the TPS performance as measured with ...
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2answers
44 views

how to find the highest IO consumer on a disk? [closed]

Can some one help to find highest IO consumer on each individual disks? i.e Which process consumes the most IO on /dev/sda, the highest IO consumer on /dev/sdb etc.
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1answer
101 views

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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4answers
331 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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1k 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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1answer
151 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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1answer
51 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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1answer
136 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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72 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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25 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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82 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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2answers
626 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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26 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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93 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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1answer
76 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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1answer
140 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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1answer
312 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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2k 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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120 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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119 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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1answer
170 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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2k 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
157 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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1answer
846 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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1answer
63 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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2answers
147 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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2answers
128 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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2answers
209 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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3answers
563 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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180 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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1answer
502 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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1answer
531 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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1answer
1k 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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1answer
44 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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2answers
4k 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 ...