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

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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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2answers
418 views

Apache2 on linux - how to track down performance trouble

I am stuck on this topic for a while now: How can I get more details on where response time burns. My Problem is the extreme variance in response times. Sometimes it takes the server 5 or 10 seconds ...
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2answers
1k views

How to turn linux to keep 'cache' high?

We are running a heavy service on Debian. Our service generates lots of file i/o and its performance relies on how well Linux kernel caches files. Our system has 64GB memory. Total file size is 500GB ...
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1answer
455 views

How long is the “defined grace period” for the idle scheduling class of the CFQ io scheduler?

The ionice man page says A program running with idle io priority will only get disk time when no other program has asked for disk io for a defined grace period. Where is this "grace period" ...
5
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1answer
1k views

How do I test the effect of ionice (against a device using the cfq scheduler)?

I'm trying to construct an experiment to measure the effect of ionice. What I'd like to do is to (per another answer on serverfault) cause frequent enough I/O that a sufficiently "niced" process is ...
3
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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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3answers
5k views

What are your tricks for optimizing your Subversion configuration?

For a Linux or Windows system, what tricks do you do to optimize your Subversion server? The following are my current tricks for a Linux system serving over Apache with HTTPS and backed by Active ...
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1answer
49 views

Ideal number of server, setup and management [closed]

Have read how large scale sites use different servers for different purpose. Here's what I have in mind: Main app - 1 server Database - 1 server Static files - Cloud hosting (e.g. AWS) Backup - 1 ...
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2answers
50k views

Tuning (and understanding) table_cache in mySQL

I ran the excellent MySQL performance tuning script and started to work through the suggestions. One I ran into was TABLE CACHE Current table_cache value = 4096 tables You have a total of 1073 ...
3
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2answers
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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1answer
536 views

How does php know what memcached node to look for its data in?

I am new to the world of Memcached clusters If I have a php web application that is using memcache - how does it does its hash and decide what node to check for a particular value to avoid having to ...
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1answer
170 views

Trade reliability for speed in a slow filesystem

On my box running Ubuntu Server 11.10 I have a rather slow soft RAID6 array on four USB sticks (and no other means for persistent storage). I want a faster filesystem on that box. I'm OK if I'd lose ...
0
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1answer
91 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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2answers
5k views

How can I configure Apache to use more of my CPU?

Apache threads are stacking up on one of my web servers (300-500 simultaneous requests, some taking 3-8s to process!), but CPU usage is very low (~10%). Page load time is slowing way down as a result....
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1answer
125 views

Apache optimization needed [closed]

What is the best values for "worker" if you have very very high traffic? Like 500M page views per day? I want to test my server with that much traffic but how can i setup to handle that much traffic ...
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1answer
4k views

Memcached Cluster - better to have 3 smaller instances or 2 mediums ones?

Currently I have 2 small servers in an memcached cluster. We are approaching out limits with them and need to grow. What are the pros/cons or going adding another small instance compared with having 2 ...
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1answer
817 views

Tuning JavaVM on AWS/EC2

there's some specific tuning JVM configuration for AmazonWS/EC2 building blocks (small, large...)? Somebody have suggestions for tuning JVM running on these machine profiles? Regards, And Past
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6answers
2k views

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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2answers
102 views

Server configurations for hosting MySQL database

I have a web application which uses a MySQL database hosted on a virtual server. I've been using this server when I started the application and when the database was really small. Now it has grown and ...
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2answers
305 views

I'm seeing performance problems with postfix accepting mail when the queue is already large, any suggestions?

I use postfix to do final delivery for a mail system I've written. So this postfix installation only accepts mail from me, and bounces. When the postfix queue is empty, it can accept a piece of mail ...
0
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1answer
1k 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 ...
3
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2answers
501 views

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 ...
4
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1answer
535 views

Ubuntu HTTP latency falling into strange quantiles

I have an Ubuntu 10.10 server with plenty of RAM, bandwidth and CPU. I'm seeing a strange, repeatable pattern in the distribution of latencies when serving static files from both Apache and nginx. ...
0
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1answer
268 views

Windows 2003 IIS webserver (testserver) is slow

I have a test environment for my Asp.Net 4.0 web applications. It runs on a Dedicated Windows 2003 Webserver (IIS 6) But it's slow! The machine never has 100% cpu and the same for memory. When I run ...
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2answers
2k views

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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3answers
6k views

Building a 1,000M row MySQL table

This question is reposted from Stack Overflow based on a suggestion in the comments, apologies for the duplication. Questions Question 1: as the size of the database table gets larger how can I tune ...
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4answers
628 views

Increase application performance on Amazon AWS

I've got a client with an MVC v1 (.NET) application running on a micro instance. On this instance, I've got .NET, IIS 7.5, and MS SQL Server 2008 running to handle the application. The client has ...
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1answer
905 views

How Do I Troubleshoot Exim Mail Retry Issues?

My server is encountering high CPU load (like almost pegged at 100%) so much that the Apache service can't run and we get Apache 500 errors. We used a script to catch this and this is where we ...
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1answer
2k views

Windows Server 2008 File Server Performance Tuning

I am running a Microsoft Windows Server 2008 R2 File Server on our network. It seems that there are many times where accessing the data from the server is really slow, sluggish, or non-responsive. ...
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4answers
23k views

Find out which task is generating a lot of context switches on linux

According to vmstat, my Linux server (2xCore2 Duo 2.5 GHz) is constantly doing around 20k context switches per second. # vmstat 3 procs -----------memory---------- ---swap-- -----io---- -system-- --...
0
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1answer
449 views

Trim out useless apache modules

I'm running a shared hosting environment with about 100 sites - I just took a peek at all the modules apache is loading/using, some of these I don't know what they are or do or if they are useful at ...
0
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1answer
945 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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3answers
1k views

Increase the performance of sort command on a multi-processor Sun Solaris box

I have a bunch of (rather large i.e. >100MB) comma separated files which needs sorting on 4 processor box with SunOS 5.10 Sort appears to run rather slow (minutes) I am wondering if there is any way ...
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1answer
91 views

Profiling windows performance

I am used to using profilers for software development. I have had multiple windows pcs which all have slowed down over time, as well as had work PCs become slower. I understand this is probably the ...
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3answers
2k views

Increasing Postfix Performance for Outbound Mail

We're trying to optimize a Dell PowerEdge 1850, Dual 3GHz procs, 3072MB RAM, running Postfix 2.8.4 and signing mail with OpenDKIM 2.4.1. iostat -x output is: avg-cpu: %user %nice %system %iowait ...
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1answer
222 views

Linux script to check settings and recommend tuning changes? [closed]

I'm searching for a script to run on our linux server and recommend various tuning changes we might consider making, as well as their suggested values for consideration. Any ideas if something like ...
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1answer
9k views

Interpreting ethtool Coalesce output

Other than tx and rx being the transmit and recieve, can anyone explain what the fields mean in ethtool -c's (Coalescing output) and what effect they have on how coalescing works? Coalesce parameters ...
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2answers
203 views

SQL performance, how to exactly measure bottlenecks

Yesterday me (programmer) and one of my coworkers from our Hosting department started series of tests to address performance issues with our websites. We are running a server with Windows Server 2008 ...
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2answers
106 views

what to check for limitations if a linux machine maxes out at a certain connection/s

I have a linux machine with a dummy HTTP server on it. It accepts a certain number of connections/second. Neither the CPU (it is a multicore) nor the memory nor IO are exhausted. What else can be ...
2
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1answer
1k views

Very long (>300s) request processing time on Apache Server serving static content from particular IP's

We are running an Apache 2.2 server for a very large web site. Over the past few months we have been having some users reporting slow response times, while others (including our resources, both on ...
0
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1answer
1k 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 ...
2
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2answers
146 views

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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2answers
2k views

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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1answer
512 views

Why is MySQL table_cache full but never used

I have been using the tuning-primer.sh script to tune my my.cnf settings. I have most things working well but the part about TABLE CACHE makes no sense: TABLE CACHE Current table_cache value = 900 ...
3
votes
2answers
771 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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2answers
163 views

How to connect an Oracle server between two countries and maintain high speeds for read & write

Our company has two branches, one in Malaysia and the other one in India. The problems occur when we try to share one of our Oracle environments to our branch in India; the connection is very slow, ...
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2answers
467 views

Troubling AB benchmarking result?

I'm a real noob when it comes to sys admin. I'm running an app on an EC2 MicroInstance. Before I launch publicly, I want to make sure that I hit a minimum level of performance. I'm trying out some ...
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4answers
343 views

Trying to scale my dedicated server for high traffic

I have a quad core xeon, 8GB ram, and only 2 x 1TB SATA drives right now. I am trying to figure out how to scale my application to handle as much load and traffic per day as possible. I have an ...
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2answers
902 views

Establish a performance baseline for terminal server windows machines

I need to establish a performace basline for our Terminal Server machines. i plan to use perfmon , and will have a SCOM server on the site very soon. The terminals are used as a desktop environment ...
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1answer
1k views

MySQL hosting: What are the recommended specs and w

I have two specific cases of MySQL hosting. 1) I have a case where I have 2000 plus concurrent users to a single MySQL Database. They are not simple web users, but actual business users who need to ...