Performance tuning is the process of modifying a system to improve its efficiency. This is also known as optimizing. Typically performance tuning refers to a computer application, but the same methods can be applied to other complex systems. The system can be a single computer program, a collection ...
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27 views
Phenomenon when there is intensive I/O operation the whole system freezes?
I've payed attention to a pattern that I've observed though out the years on development machines (common hardware, Intel motherboards).
When I cause heavy I/O operations that whole system becomes ...
0
votes
2answers
30 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 ...
-2
votes
1answer
34 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 ...
2
votes
4answers
106 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 ...
7
votes
3answers
170 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 ...
1
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2answers
59 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
0answers
38 views
Combined random and sequential I/O for a database
We need to size a storage that will host the datadirs of many running slave instances of MySQL. The storage shall be connected to a single server that will run all the slave instances.
On the ...
0
votes
2answers
96 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 ...
0
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0answers
124 views
tuning low memory apache server for “high traffic” web
I get between 3500 and 5500 visits a day on a beta web app that I developed and launched a couple of months ago. The app has no use of a database and has very few files, so mysql queries and file ...
3
votes
2answers
76 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 ...
0
votes
0answers
88 views
Shared folder access from ubuntu is too slow
I've a NAS. From a windows machine it takes 1 or 2 seconds to access shared folders. From Ubuntu (11.10) it takes half a minute only for shows me the credential dialog box and another half to log in ...
0
votes
2answers
77 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 ...
-2
votes
1answer
34 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
488 views
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 ...
5
votes
1answer
112 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 ...
0
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0answers
26 views
issues with IEEE authentication
We have an application managing other systems in the network solving thier issues.After some days it became un-responsive (applications became unresponsive and windows freezes)
I have confirmed ...
0
votes
0answers
55 views
Free benchmark tool for evaluating the performance of server side Java [closed]
Do you know a free benchmark tool for evaluating the performance of server side Java for Linux?
In the literature SPECjbb2005 is often used for this purpose but there isn't a free version.
I need to ...
2
votes
1answer
78 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 ...
2
votes
2answers
74 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 ...
2
votes
2answers
128 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 ...
4
votes
1answer
64 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
91 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
votes
0answers
92 views
Long time to first byte for static content
I have large time to first byte for static content on IIS 7.5, it's not site specific it's slow for all sites on that server. runAllManagedModulesForAllRequests is set to false, and gzip is enabled ...
0
votes
1answer
84 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" ...
1
vote
4answers
167 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 ...
1
vote
1answer
96 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)
4
votes
2answers
182 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 ...
0
votes
1answer
45 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
160 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
67 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
275 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
81 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
1
vote
1answer
322 views
NGinx vs Varnish as a reverse proxy in front of Apache w/php
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 ...
0
votes
2answers
71 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
107 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
134 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 ...
0
votes
2answers
130 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
129 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
200 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
100 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
234 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
...
0
votes
1answer
239 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, ...
9
votes
3answers
396 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 ...
-1
votes
2answers
84 views
How to perform Server Performance Audit [closed]
Here is the situation. I am the CIO in my work place. The guy on the management team that get to take decision regarding Techy things. I dont do actual development, but we have an IT service provider ...
0
votes
1answer
181 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
185 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. ...
2
votes
1answer
398 views
what does locked % in mongostat mean?
When running mongostat to look at our mongo database, I'll frequently see the locked % number jump up, sometimes as high as 80%. Here's a few example rows:
insert query update delete getmore ...
0
votes
1answer
104 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
votes
1answer
271 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
269 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 ...
