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

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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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Optimizing RAID 5 for BackupPC use (small random reads)

I am running a BackupPC server with a hardware RAID 5 for the main storage of the backups. Since the machine was created on a tiny budget, the controller is a 3Ware 9500S-4LP for the PCI port and the ...
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MySQL performance tuning

I'm looking for a succinct list of common pitfalls and optimizations for tuning a MySQL server as used for mid-size websites. In general, the type of advice I'm looking for here is information that ...
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Database I/O acceleration using solid state drives

What is the experience improving database performance using solid-state drives (particularly for PostgreSQL databases) such as HP's IO Accelerator? Did you see any marked improvements?
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HP P410 RAID + Samsung 830 SSDs + Debian 6.0 - What performance to expect?

I'm renting two dedicated servers from a hosting company. Here are the specs: server1: HP ProLiant DL165 G7 2x AMD Opteron 6164 HE 12-Core 40 GB RAM HP Smart Array P410 RAID controller 2x Samsung 830 ...
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276 views

How to profile for HDD usage pattern?

I'm considering upgrading the storage system for some of my servers, and all the guides and manuals advise to consider the storage usage patterns of your app before deciding on a (RAID? SSD? iSCSI? ...
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Improving OpenVPN Performance

I've been trying to improve my OpenVPN performance and this is my current setup: cat /etc/openvpn/server.conf port 443 #- port proto tcp #- protocol dev tun #tun-mtu 1500 tun-mtu-extra 32 #mssfix ...
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Lot of FIN_WAIT2, CLOSE_WAIT , LAST_ACK and TIME_WAIT in Haproxy

We are running haproxy in production for around 10k+ concurrent users. But we are seeing lot of FIN_WAIT2, CLOSE_WAIT , LAST_ACK and TIME_WAIT in the netstat output. This output is on a 8G ubuntu-12....
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Openfiler iSCSI performance

Hoping someone can point me in the right direction with some iSCSI performance issues I'm having. I'm running Openfiler 2.99 on an older ProLiant DL360 G5. Dual Xeon processor, 6GB ECC RAM, Intel ...
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151 views

Measuring I/O Performance Paradox

I'm trying to figure out the correct way to get the 'real world' write performance of my NFS cluster. The NFS export is mount on a XEN hypervisor, and I'm running 'dd' from within a VM. What I can'...
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It is possible move a specific file to the beginning of the disk?

It is possible move a specific file to the beginning of the disk? I want to move my virtual machine disk files (virtual disk) to the beginning of the disk to improve disk access performance. I believe ...
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How can I make this setup faster?

Hey StackOverlow Community, I currently am using some software that stores a bunch of XML files. All the files are under 25k bytes. The makers of the software state the performance is based on ...
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Changing memory allocator to Jemalloc Centos 6

After reading this blog post about the impact of memory allocators like jemalloc on highly threaded applications, I wanted to test things on a larger scale on some of our cluster of servers. We run ...
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1answer
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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: http://www.experts-exchange.com/OS/Linux/...
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625 views

httperf hangs when using --hog

I'm using httperf from a large ec2 instance with ubuntu 10.04 (no other software installed). When I test without --hog the tests run however when I use --hog the tests never end
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Linux's best filesystem to work with 10000's of files without overloading the system I/O

It is known that certain AMD64 Linuxes are subject of being unresponsive under heavy disk I/O (see Gentoo forums: AMD64 system slow/unresponsive during disk access (Part 2)), unfortunately have such ...
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328 views

What are some current and relevant benchmark tools for Linux?

I'm specifically interested in benchmarks that approximate or target real in the wild usage scenarios. My main areas of focus are latency, network performance (incoming data over sockets). ...
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927 views

What should I set the initial MySQL Values in My.cnf to for Performance?

I am just setting up my new Linux Ubuntu 8.04 LTS server now, and getting ready for launch. My application is a PHP built application using the Zend Framework, and there is a MySQL heavy site (as are ...
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Optimizing storage of 10-20 million files on RAID5 (currently using LVM+XFS)

Although I've browsed some of the questions here, I think every situation is different and maybe requires a totally different solution. What I have now: Linux software RAID5 on 4x4TB enterprise HDD ...
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2answers
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ApacheTop like tool for Nginx for measuring hit contents?

Are there ApacheTop like tool for Nginx for measuring hit contents? I want to find out the most popular URL from the web server log (Nginx)
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2answers
766 views

PostgreSQL tuning recommendation for large server and dataset

I'm working with a PostgreSQL (8.1) server on a dedicated machine with 64 GB of RAM and a fast RAID disk. The data set itself is pretty huge -- we have several tables around 200 GB, more in the 50-100 ...
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590 views

How to identify which MySQL queries take a lot of time?

My MySQL server is consuming a lot of memory. Memory footprint 1. Memory consumption in descending order (top 4) MySQL's memory consumption in particular - Why is there so many number of mysqld ...
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Manage Win7 Performance Options via GPO

Our company has many virtual Windows 7 instances. Based on recommendations from VMWare, we want to customize the visual effects to optimize performance. We have found that we can change the following ...
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Tuning MySQL and Linux to reduce maximum response time specifically

We have a MySQL-based application that is very response time sensitive. A MySQL stored procedure needs to respond on average in less than 10 milliseconds and the maximum acceptable response time is 50 ...
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How to adjust MySQL performance

I'm facing a real problem with MySQL instance for a service online. We use hibernate and c3p0 pool with these settings: c3p0.max_size=200 c3p0.min_size=5 c3p0.timeout=60000 c3p0.max_statements=20 ...
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what are the memory impacts of increasing a NIC's ring buffer?

What impact (if any) does NIC ring buffer tuning (e.g. via ethtool -G eth0 …) have on system memory utilization? For example, does increasing the ring buffer consume more RAM? And if so, how much? Or ...
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Is RSS (receive side scaling) in Windows considered unstable?

When asking a customer to enable RSS in their data center to improve network performance (very high UDP packets-per-sec rate), I was told that they generally turn it off, because after various ...
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407 views

Preventing PHP-FPM from crashing under light load

I'm getting a DoS attack on a wordpress site that I host. 173.192.109.118 - - [30/Sep/2015:22:31:36 +0000] "POST /xmlrpc.php HTTP/1.0" 499 0 "-" "Mozilla/4.0 (compatible: MSIE 7.0; Windows NT 6.0)" ...
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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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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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2answers
474 views

IIS 7 — how to track down mysterious network & cpu usage?

I've got a 64-bit Server 2008 (R1) box running IIS. Users were complaining about extremely slow-loading pages. After digging around I found: After isolating the box so only one user was able to ...
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How to remove the pause during JBoss 5.1.0 GA boot between ProfileServiceBootstrap and AnnotationCreator?

I've managed to strip down my JBoss profile enough that it boots in 1.5 minutes. I started with the web profile and started pulling out stuff I didn't need. The bulk of my boot time can be seen here: ...
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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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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 ...
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How can I improve NFS performance on a gigabit LAN?

I have a Solaris 10 server with a Mac OS X clients on a gigabit LAN. The Solaris server exports a RAID-Z backed NFS share and all the clients connect to it. However, transferring files is slower ...
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Does Overclocking Anything Shorten It's Life? [closed]

From a business standpoint... If intel could take a 3.0 GHz CPU, and overclock it to 4.0 GHz - whilst still covering their warranty they would do so. It's absolutely free and makes the chip perceived ...
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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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switching to worker mpm for apache 2 on ubuntu

How to switch from prefork mpm to worker mpm on ubuntu server? how to roll back if there is any problem? root@myserver:~# apache2ctl -l Compiled in modules: core.c mod_log_config.c mod_logio.c ...
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How to optimize iptables for high DNS traffic?

How to optimize iptables for high DNS traffic? I have a dedicated linux server acting as bridged firewall using iptables. Recently behind firewall was deployed DNS server with high load and firewall ...
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1answer
135 views

What resources on OpenVMS Performance Management do you recommend?

I'm looking for details about how to measure OpenVMS performance, such as what all of the different reported statistics mean and how to adjust for them. In particular, I'm currently investigating ...
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6answers
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Looking for comparisons of disk i/o for a dedicated MySQL server

We hired a consultant to help us increase the capacity of our MySQL cluster, and the first thing (almost only thing) he did was to measure the disk i/o speed of our servers. I am interested in a ...
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Slow write Performance with HP H240 HBA using internal Storage with Raid 5 SSD's

I am having a HP Proliant DL 160 Gen9 Server with a HP H240 Host Bus Adapter. 6x 1 TB Samsung SSD's configured in a raid 5 directly using the internal storage of the machine. After installing a VM on ...
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1answer
282 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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2answers
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Apache with prefork model using 1000 MB memory per process

I am currently working on a site which uses Apache running on the prefork memory model. The following is the configuration from httpd.conf <IfModule prefork.c> StartServers 30 ...
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1answer
150 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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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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Does deleting unused files such as images, javascript, xml, html, asp etc make your Windows Server faster?

I have an IIS7 Windows 2003 Dedicated server. I just wanted to know if I delete old files such as XML, HTML, ASP, PHP, images, CSS, JavaScript.. etc.. files that are no longer used.. Does this ...
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Filesystem/Options for intensive random I/O

I'm planning to (privately) deploy a server that will be hammered with random I/Os in files ranging from 100MB to 50GB. The requests will range from 128 KB to 4MB. The profile will be 50:50 concerning ...
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1answer
104 views

Server load avg. hitting 16-20, but all resources under 90% usage?

As you can see in the image shared below, the server load peaked to almost 20 but the CPU, RAM, DISK IO and Network I/O remained well under their full capacity. My question is: 1). What caused the ...
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622 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: ...