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

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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 ...
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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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1answer
3k views

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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1answer
80 views

Server hanging when serving random file on page load

I'm optimising a website, and the problem I'm facing with now is server related. During page load, there are about 40-50 requests sent to server (depending on the page), and in every case, server ...
2
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1answer
567 views

Different block sizes for partition and underlying logical disk on HP Raid Controller (Linux)

Following links collected in this thread I started to check blockdev and found the following output indicating different sizes for partition c0d9p1 and the underlying device (c0d9): [root@machine ~]# ...
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219 views

Can I tune my Debian KVM server to benefit my Windows guest?

Debian Squeeze KVM server with Win2k8 server guest. The server has 16GBs of RAM and the guest only runs MS SQL, with a 15GB database on it. I am wondering if there is anything I can tune from the ...
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591 views

Perfmon - Redirector current command 0 result

I'd like to monitor how many SMB connections there are at any given time for my 2008R2 file server, but when I add Redirector/Current Commands in perfmon, I get 0 results. This KB from Microsoft isn't ...
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134 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 ...
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4answers
18k views

How to achieve 500K requests per second on my webserver? [closed]

I recently gifted myself a new dedicated server and I am trying to squeeze maximum performance out of it, for fun and learning. I am trying to achieve maximum possible requests per second this server ...
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7answers
15k 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 ...
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1answer
296 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 ...
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4answers
815 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 ...
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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 ...
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163 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 ...
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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 ...
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3answers
468 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 ...
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2answers
376 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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2answers
448 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
1k 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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1answer
47 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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3answers
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Linux - real-world hardware RAID controller tuning (scsi and cciss)

Most of the Linux systems I manage feature hardware RAID controllers (mostly HP Smart Array). They're all running RHEL or CentOS. I'm looking for real-world tunables to help optimize performance for ...
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1answer
1k 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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1answer
882 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 ...
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2answers
149 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 ...
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2answers
241 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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1answer
381 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
162 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 ...
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1answer
323 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" ...
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5answers
1k views

Windows Server 2008 R2 poor CPU performance

We have two identical servers with the following specs: 4 sockets containing AMD Opteron 6172 at 2.10 GHz each of which have 12 cores 64 GB RAM One runs Windows Server 2008 R2 Standard, which ...
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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)
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2answers
625 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 ...
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84 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
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 ...
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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 ...
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1answer
254 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 ...
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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 ...
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580 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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1answer
978 views

NGinx vs Varnish as a reverse proxy in front of Apache w/php [closed]

I am using apache with mod_php to serve content. Mostly the content is fetched form memcache over the network. All of my images, css and js are already on a cdn What are the pros and cons of putting ...
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2answers
97 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
251 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 ...
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1answer
866 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 ...
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3answers
524 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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2answers
377 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 ...
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1answer
501 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. ...
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1answer
244 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
1k 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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596 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, ...
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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 ...
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692 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 ...