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

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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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1answer
137 views

Server optimization for long running script [duplicate]

I have a system running on a remote VPS whose main feature is a long running script (it could run for about 10 hours, depending on the user input). The following are some of its features: Database ...
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247 views

How to avoid Memory “Hard Fault/sec”

i've a problem on my windows 2008 server x64, and i cannot understand how can i solve it. i'm looking to Resource Monitor and see about 100 to 200 hard faults/sec. and generally the machine is slow. ...
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3answers
2k views

Understanding RedHat's recommended tuned profiles

We are going to roll out tuned (and numad) on ~1000 servers, the majority of them being VMware servers either on NetApp or 3Par storage. According to RedHats documentation we should choose the ...
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3answers
922 views

Strategy to optimize raid cache

HP SmartArray have "Accelerator Ratio: XX% Read / YY% Write", that configures how much cache ram dedicated for read, and how much for write. Is there way to find best proportion on alive server in ...
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2answers
980 views

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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1answer
124 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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4answers
2k views

Lower Maximum Possible Memory Usage

I've been using MySQLTuner to optimize my database, and the only problem I am having is: [!!] Maximum possible memory usage: 14.8G (126% of installed RAM) I'm not sure what I should be ...
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1answer
68 views

IIS - Overuse of memory is normal? [closed]

I have two servers running Asp.net applications. Sometimes applications are too slow and memory usage seems exaggerated. Specifications: SERVER #1 OS: Microsoft Windows 2003 R2 Memory: 4GB ...
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1answer
302 views

HP DL360p Gen8 for low latency trading - what to upgrade? [closed]

I'm using HP DL360p Gen8 for low latency trading (but not ultra-low-latency!). It means that i'm working in frame about "10+ microseconds" and i don't care about "1-5 microsecond" or nanoseconds. I ...
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1answer
852 views

How do I disable “Processor Power and Utilization Monitoring” on an HP ProLiant server?

I'm tuning my server for low-latency The guide suggests to disable this option "Processor Power and Utilization Monitoring" because: Disables iLO Processor State Mode Switching and Insight Power ...
2
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1answer
242 views

Apache high CPU usage, setting a overload limit

On a ubuntu server, I run a LAMP environment with APC, and fast-cgi as php mod, to host 2 wordpress sites, and both sites have Wordpress Total Cache (W3TC) plugin configured. The server's specs are: ...
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1answer
188 views

TCP RWIN, MSS and MTU [closed]

I have been doing some reading into TCP Receive Window (RWIN), Maximum Segment Size (MSS) and Maximum Transmission Unit (MTU). Right off the bat I have some questions and I need a power user's help! ...
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1answer
115 views

epoll timeout configuration in lighttpd

Is there a configuration option to tune epoll timeout in lighttpd? I'm developing an embedded Linux (2.6) device, with lighttpd 1.4.30. And I'm observing the following issue: even when the system is ...
0
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1answer
29 views

Before buying it, how can I tell if a storage array makes certain performance counters available over SNMP?

I've noticed that documentation for SNMP reporting that is built-in to devices (i.e. doesn't need an agent running in an OS) usually doesn't include a list of performance counters that are available ...
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1answer
226 views

Why am I getting a Sudden Drop in throughput and sluggishness with no CPU increase

Occasionally, during random parts of the day, I get a 10 minute period of extreme sluggishness where my requests are taking 50-1000 times longer then they normally do. Note: I am on Apache/2.2.16 ...
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2answers
5k views

Should we mount with data=writeback and barrier=0 on ext3?

We've been running a server on a VM at a hosting company, and have just signed up for a dedicated host (AMD Opteron 3250, 4 cores, 8GB RAM, 2 x 1TB in software RAID, ext3). While running performance ...
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2answers
405 views

virtual memory optimization on exchange server 2010

Hi I did some Google searching but came up blank I know mycomputer/computer > Properties > advance System settings > Advance[tab] > Settings[Performance] > Advance [Tab] > Change > customsige ...
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0answers
180 views

TCP tunning for ssh port forwarding [closed]

I am using an ubuntu openssh server to allow users to connect to and do dynamic port forwarding. the performance is good until about 100 users are connected. beyond that the performance is dropped too ...
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1answer
3k views

Apache HTTPD configuration for high load [duplicate]

Good day, I want to be able to serve at least 7000 (preferably 10k) concurrent requests from my Apache Httpd. I have configured my httpd.conf with MPM worker with the following setup ServerLimit ...
8
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2answers
733 views

Linux RAID-0 performance doesn't scale up over 1 GB/s

I have trouble getting the max throughput out of my setup. The hardware is as follow : dual Quad-Core AMD Opteron(tm) Processor 2376 16 GB DDR2 ECC RAM dual Adaptec 52245 RAID controllers 48 1 TB ...
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260 views

Copying cause big iowait

I have dedicated server with 3 HDD. System disk, backup disk (same as system disk) and data disk. When I copy lot of data with cp (say, between backup disk and data disk) load average goes sky high. ...
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1answer
924 views

Why change net.inet.tcp.tcbhashsize in FreeBSD?

In virtually every FreeBSD network tuning document I can find: # /boot/loader.conf net.inet.tcp.tcbhashsize=4096 This is usually paired with some unhelpful statement like "TCP control-block hash ...
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2answers
216 views

How does one 'qualify a server'

Here is the scenario. Say you are going to be a purchasing great deal of servers, but first are trying out hardware from a vendor, and you need to qualify it. Also, say that the custom software that ...
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184 views

RAID10 (4x SSD) system is super slow for 'dd' and 'find' commands

I have configured two servers each with 32 GByte RAM, 2x Xeon 2.4 GHz, 4x 480 GByte Intel SSD on a LSI MegaRAID SAS 9261-8i controller. They should be identical, however one of them has a very poor ...
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429 views

Ubuntu 12.04 64bit - What would cause high System CPU %sys during high MySQL loads?

128GB RAM, 32cores Xeon RAID 10 SSD. Mysql version is the latest 5.5 for Ubuntu 12.04 . We have a lot of queries - about 1800+ per second. During high MySQL load - 2700+% load on a 32 CPU system - ...
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3answers
473 views

Disk write speed much slower than read speed

I have a VPS server (WiredTree), running CentOS. After experiencing some performance issues I created a simple benchmark for disk read/write speed using the following script: echo Write to disk dd ...
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0answers
43 views

Job run-time variations on dual socket computer

I'm running scientific software (WRF-NMM, atmosphere simulation, weather prediction). On all computers I used it, job running times of run cycles were consistent. All those machines were one socket, ...
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2answers
2k views

CPU0 is swamped with eth1 interrupts

I've got an Ubuntu VM, running inside Ubuntu-based Xen XCP. It hosts a custom FCGI-based HTTP service, behind nginx. Under load from ab the first CPU core is saturated, and the rest is under-loaded. ...
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2answers
286 views

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 ...
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3answers
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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2answers
673 views

Troubleshooting poor disk IO performance

Note that while this question is a little Redis-specific, the main problem is generic: a process takes so much HDD IO write bandwidth that other processes can't write anything. We've got an Ubuntu VM ...
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1answer
1k views

Strange high CPU I/O wait on postgresql server

I'm really struggling with a performance issue currently, where all my database queries takes up to a 1000 times more than normally, when my database server is under "heavy" load. I have a server ...
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6answers
2k views

How to know if my nginx is in good health?

I am running a nginx on EC2 (m1.small) for SSL termination. I am using 2 workers on Ubuntu, with latest nginx (stable), the network throughput is around 2Mbps and system load average is around 2 to ...
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7answers
2k views

Linux tool/command to check file system performance

What is the simplest way to check read/write performance to a specific location (e.g. a mounted iSCSI device). I suspect I can't use hdparm because that's lower level. Am I right?
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277 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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0answers
84 views

Getting the virtual memory address for (major) page faults

On a Linux (Cent OS 5) system, I have a process that accesses a large amount of memory mapped files. The process is generating a large amount of page faults because the aggregated size of the mapped ...
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1answer
198 views

Which will give more free RAM to linux? [closed]

Trying to avoid some issues so I've been trying to learn vm. in kernel tuning but still a little confused even after googling. The lower background_ratio is the sooner the flushes? the lower ...
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1answer
406 views

VM Tuning to enhance performance

vm.bdflush = 100 1200 128 512 15 5000 500 1884 2 vm.dirty_ratio = 20 vm.dirty_background_ratio = 10 vm.swappiness = 10 vm.min_free_kbytes = 300000 That means that the MOST dirty data that can be in ...
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1answer
145 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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1answer
215 views

CFQ vs Deadline - performance benefits [closed]

Running CPanel and wondering what would be the best for web hosting? deadline is more balanced over CFQ right so would allow for more I/O activities right
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1answer
2k views

Disabling CPU management

If I add the following processor.max_cstate=0 to the kernel command line for boot up, does that disable all CPU power management and throttling? I also found: ...
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1answer
87 views

MySQL Threads or what is this

http://i.stack.imgur.com/dZFqI.png How can I reduce that number? I have a quad core machine. Do I need to edit thread_pool_size and by reducing them do I get better performance? Should a lot of ...
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1answer
198 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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1answer
563 views

How do change the max IO request size on Windows Server 2008 R2

As I understand it Windows Server 2008 R2 has the ability to send IO requests to the storage subsystem of up to 1MB in size. Back in the Server 2003 era (and before) this used to be limited to 64KB. ...
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1answer
2k views

JVM tuning in JBOSS AS 7

Can anyone explain as to where and how do I configure the following JVM parameters to tune JBOSS. I am using the latest JBOSS AS 7. I am using openJDK-6 on Linux. The following are the parameters ...
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13answers
6k views

Postfix performance

Running postfix on ubuntu, sending alot of mail ( ~ 1 million messages ) per day. loads are extremly high but not much in terms of cpu and memory load. Anyone in a similiar situation and know how to ...
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1answer
200 views

RRAS (Routing and Remote Access) change process priority to “realtime”?

I have a windows server 2012 running RRAS and some other services. Beacause of that I guess I have experience some slowdowns and dropout of package. My question is how to find, and change the ...
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2answers
746 views

How to tune down the Hyperic built-in postgresql database for a small setup

We are testing out Hyperic 4.5.1 in a quite small environment for now. Currently there are just 1-5 agents and there probably won't be any more than 10-15. When I run ps ax there are 20(!) postgres ...
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1answer
330 views

Doubled up RAM to 32 GB - now how to speed up a “LAPP” server?

I run a small Facebook game at a CentOS 6.3 quad core machine with PostgreSQL 8.4.3 + few PHP scripts (doing mostly select queries) + 1 Perl daemon and even though the server worked ok, I've suggested ...