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

learn more… | top users | synonyms

0
votes
1answer
287 views

adding new scheduling policy to the kernel

i'm working on a redhat 8 linux and i want to add new policy for scheduling the processes , could you help me with : 1) where to define the new policy 2) how does the process of assigning a policy for ...
6
votes
1answer
137 views

How to prevent IO Load under Linux for Video serving?

I'm currently serving videos of conferences via Nginx on 3 servers; 4 cores, enough memory (no swap used) and RAID-10 with 8 drives per server. Unfortunately iostat -xd 1 gives me 100% on all 3 ...
13
votes
7answers
19k views

Apache Tomcat chokes after 300 connections

We have an apache webserver in front of Tomcat hosted on EC2, instance type is extra large with 34GB memory. Our application deals with lot of external webservices and we have a very lousy external ...
0
votes
4answers
909 views

Exchange 2010 SP2 OWA performance

How do I increase performance in OWA 2010 SP2? I am running CAS on a seperate installation, which has 8GB RAM and 4 CPU cores - running virtualized in a vmware environment. However, the load times ...
0
votes
1answer
333 views

Linux kernel 3 TCP IP tuning

I found several resources about tuning linux TCP/IP stack parameters in /etc/sysctl.conf for high bandwidth connections, but all refer to kernel 2.6. Does anyone have suggestions about how to tune ...
0
votes
2answers
57 views

How can I decide up the nature of performed IO?

I am using Linux (3.2.12-3.2.4). I have few "syncer" processes which updates lots and lots SQLite db files in a loop. The database sizes vary from 1 MB to few GB. I have a "searcher" process which ...
7
votes
3answers
480 views

Unexplained periodic humps in system CPU usage on W2K3E

We have a Windows 2003 R2 Enterprise 64-bit server running a custom workload suffering from an odd performance problem. The pared-down version below suffers from a smaller hump, but it's qualitatively ...
4
votes
2answers
673 views

ratelimit POST requests

Im running a large wordpress multiuser site. I have a varnish cache infront of the wordpress application server. As it make no sense to cache POST requests, i am vulnerable to DOS using lots of POST´s ...
-3
votes
1answer
166 views

Can a large number of network hardware interrupts cause a machine to be underutilized?

I don't know much about networking sorry. I'm building a client / server where the server streams a lot of data to the client and I'm trying to maximise throughput (through TCP). If I run both client ...
3
votes
4answers
1k views

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 ...
1
vote
2answers
385 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 ...
0
votes
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 ...
3
votes
1answer
356 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
votes
1answer
937 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
votes
2answers
456 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 ...
7
votes
3answers
4k 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 ...
-2
votes
1answer
48 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 ...
12
votes
2answers
41k 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
votes
2answers
150 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 ...
4
votes
1answer
409 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 ...
0
votes
1answer
166 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 ...
3
votes
1answer
1k views

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)
0
votes
1answer
86 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 ...
0
votes
2answers
3k 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 ...
-3
votes
1answer
121 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 ...
1
vote
1answer
3k 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 ...
-1
votes
1answer
641 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
2
votes
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 ...
0
votes
2answers
101 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 ...
1
vote
2answers
255 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
votes
1answer
935 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
votes
2answers
412 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
votes
1answer
510 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
votes
1answer
252 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 ...
2
votes
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 ...
13
votes
3answers
3k 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 ...
0
votes
1answer
655 views

Improving TCP performance over a network with small packet loss

I’m trying to improve my TCP throughput over a “high delay network”, with some packet drops, between Linux machines. I set tcp_mem, tcp_wmem and tcp_rmem to “8192 20530752 20530752”. I set rmem_max, ...
0
votes
4answers
477 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 ...
1
vote
1answer
739 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 ...
1
vote
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. ...
5
votes
4answers
14k 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
votes
1answer
399 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 ...
6
votes
4answers
7k views

Windows 7 network performance tuning for LAN

I want to tune Windows 7 TCP stack for speed in a LAN environment. Bit of background info: I've got a Citrix XenServer set up with Windows 2008R2, Windows 7 and Debian Lenny with Citrix kernel, ...
0
votes
1answer
768 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 ...
0
votes
3answers
904 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 ...
2
votes
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 ...
1
vote
3answers
1k 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 ...
-1
votes
1answer
214 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 ...
7
votes
1answer
6k 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 ...
1
vote
2answers
176 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 ...