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

learn more… | top users | synonyms

3
votes
3answers
474 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
3
votes
2answers
495 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 ...
3
votes
1answer
203 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 ...
3
votes
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 ...
3
votes
2answers
332 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 ...
3
votes
2answers
1k 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 ...
3
votes
1answer
2k views

What is the best TCP congest algorithm to use for a mobile device?

Given the multitude of TCP algorithms available now and the rise of Linux based mobile devices, what are ideal algorithm(s) to consider? From reading of the various implementations, Veno and ...
3
votes
0answers
177 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 ...
3
votes
2answers
437 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 ...
3
votes
1answer
636 views

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: ...
3
votes
2answers
283 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 ...
2
votes
3answers
4k views

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 ...
2
votes
1answer
816 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
votes
5answers
400 views

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 ...
2
votes
2answers
214 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 ...
2
votes
3answers
1k views

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 ...
2
votes
1answer
121 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 ...
2
votes
5answers
1k views

What could be causing memory creep on a VPS?

I've got a VPS package. I cannot log into my lxadmin because it is "out of memory". In HyperVM I see that my VPS is using 240 MB of 256 MB. When I reboot the HyperVM, the memory goes down to 2 MB. ...
2
votes
3answers
450 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 ...
2
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 ...
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 ...
2
votes
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 ...
2
votes
2answers
142 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 ...
2
votes
1answer
50 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 ...
2
votes
1answer
234 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: ...
2
votes
2answers
312 views

dedicated apache httpd server configuration and performance tuning

I have the following dedicated box that I only install apache httpd server on, what parameters in httpd.conf should I tune to achieve max performance? cat /proc/cpuinfo shows 8 processors(only ...
2
votes
2answers
636 views

perf tuning for ESX vmfs3 on RAID

looking for recommendations on ESX4 OS - VMFS version3: RAID-5 : matching the stripe size with VMFS block size? (64K, 128K etc) RAID controller options: "adaptive read ahead, write-back" on PERC 6i ...
2
votes
1answer
36 views

Execute ps1 script when CPU threshold is meet

I'm looking for a function similar to Debug Diagnostics Collector. Where you can setup a performance (or any counter) trigger (eg. above 50% CPU over 50 seconds). Once condition of a trigger are ...
2
votes
1answer
3k views

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 ...
2
votes
2answers
772 views

Too much I/O generated by postgres stats collector process

I am using XenServer with several virtual machines having local postgres databases. Even when all applications are unused and the databases are idle, each vm causes constant storage network traffic ...
2
votes
1answer
4k views

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 ...
2
votes
1answer
1k views

InnoDB options crashing mysql start AND mysql tuning

I have an innodb on a Ubuntu 10.10 server running on an ESXi platform. I have dedicated 8 CPUs, 32 Gigs of ram, and files stored in a Raid 5 HP SAN of SAS 10k rpm disks. I'm expecting FAST queries! ...
2
votes
5answers
328 views

Figuring out what's causing a server to slow down

I have a potential client that has a php site that performs fine most of the time. However, every week or so, it will experience lag (slow page loading). I am sure there are a myriad of things that ...
2
votes
1answer
261 views

Do IIS App Pools using Network Service account share memory?

We're trying to tune our IIS farm, and I'm trying to get my head around how Windows allocates resources in our current setup. We have a pretty standard layout. We host 30+ ASP/ASP.NET sites on our ...
2
votes
2answers
1k views

Can tail slow down log writing speed on Linux (ext3)?

I'm wondering if tailf can generate blocking I/O which will slow down server responsiveness due to logging. For ex. assuming the following setup: Debian 5.1 linux server (foo) which is managed via ...
2
votes
1answer
88 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 ...
2
votes
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 ...
2
votes
1answer
203 views

Outbound HTTP performance tuning recommendations

I'll detail my exact setup below, but general recommendations for a better web-browsing experience will be useful. A nice checklist of things to try would be great! I have 600 users on a single site ...
2
votes
2answers
817 views

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 ...
2
votes
1answer
72 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
votes
1answer
459 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 ~]# ...
2
votes
2answers
2k views

How to make setting of kern.ipc.somaxconn persistent?

Want to rise value of kern.ipc.somaxconn With sysctl works ok $ sudo sysctl kern.ipc.somaxconn=2048 $ kern.ipc.somaxconn: 128 -> 2048 check it: $ sysctl -a|grep somaxconn ...
1
vote
2answers
4k views

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 ...
1
vote
5answers
3k views

VPS hosting is very slow. What's the bottleneck?

I've setup a new VPS hosting, to run a Drupal website but it is extremely slow. It is Ubuntu 10, Apache, php5.2 I've enabled Multi-Processing Module (MPM) module and configured it as follows: ...
1
vote
3answers
93 views

SQL Server Tuning Resources

I want to learn more about tuning SQL Server instances (2005/2008), does anyone have any good resources they can point me at? Dave NB: I'm talking about the hardware/instance configuration side of ...
1
vote
5answers
671 views

Trouble shooting wireless signal performance

I just performed a wireless network scan and my primary wireless route broadcasts a consist 70 DBm signal. I added a range extender that increases or decreases the signal 65 DB (Not sure how the DB m ...
1
vote
2answers
135 views

Visualize overloaded nic in linux (kernel time)?

I have a linux server that keeps getting its NIC overloaded and I need to visualize how and why this is occurring based on connections and CPU utilization. How do I do this? For example; for me to ...
1
vote
3answers
2k views

How-to manage a MySQL table with over 2 million records

I have an InnoDB table running on MySQL 5.0.45 in CentOS. To make matters worse it is all running in a virtual machine. There are multiple tables that have the probability of exceeding 2 million ...
1
vote
2answers
3k views

Interpretation of non-zero vmstat “bi/bo” values

What are useful rule-of-thumbs with regard to interpreting non-zero vmstat "bi/bo" values? When are the values "okay" and when are they an indication of that the system is under heavy stress? The ...
1
vote
2answers
505 views

How well does Windows 7 Handle High Bandwidth-Delay Product Networks

As WAN bandwidths increase default network settings in older operating systems are less and less able to efficiently use the network. A description of the problem with high bandwidth-delay product ...