Questions tagged [tuning]
53 questions
104
votes
8 answers
What limits the maximum number of connections on a Linux server?
What kernel parameter or other settings control the maximum number of TCP sockets that can be open on a Linux server? What are the tradeoffs of allowing more connections?
I noticed while load testing an Apache server with ab that it's pretty easy to…
Ben Williams
- 2,376
- 4
- 21
- 17
41
votes
3 answers
MySQL lowering wait_timeout value to lower number of open connections
I run a rather busy site, and during peek hours I see over 10.000 open connections to my database server on my webserver when a run a netstat command. 99% of the connections are in the TIME_WAIT state.
I learned about this mysql variable:…
Mr.Boon
- 1,471
- 4
- 24
- 43
39
votes
5 answers
How to identify I/O bottlenecks on a Linux server?
How do you determine that the performance of your Linux server is I/O bound and, perhaps more importantly, what process or processes are casuing the problem?
cletus
- 9,999
- 9
- 37
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30
votes
5 answers
Need to increase nginx throughput to an upstream unix socket -- linux kernel tuning?
I am running an nginx server that acts as a proxy to an upstream unix socket, like this:
upstream app_server {
server unix:/tmp/app.sock fail_timeout=0;
}
server {
listen ###.###.###.###;
server_name whatever.server;
…
Ben Lee
- 666
- 2
- 9
- 24
26
votes
3 answers
What value of thread_cache_size should I use?
I'm using Asp.Net together with MySQL. In the .Net connection string, I have set Max Pool Size to 150.
If I run the following I get these values:
SHOW GLOBAL STATUS LIKE 'max_used_connections'; gives 66
SHOW GLOBAL STATUS LIKE 'Threads_created';…
Martin
- 379
- 1
- 3
- 11
21
votes
4 answers
Why would a heavily disk intensive application run faster on a SAN than on a Physical Disk?
Why would a heavily disk intensive application run faster on a SAN than on a Physical Disk? I would have expected the Physical disk to be slightly faster but in fact the process ran 100 times faster when it's work drive was set to a partition on the…
Stuart Woodward
- 1,343
- 4
- 14
- 29
15
votes
4 answers
kjournald reasons for high usage
I'm trying to figure out why is kjournald going crazy on my machine. It's an 8-core box with loads of memory. It's got ~50% cpu load.
The iotop doesn't seem to point at any specific processes - some bursts of writes here and there (mostly cron…
viraptor
- 1,296
- 6
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- 41
12
votes
4 answers
How to best tune a Windows development machine?
How to best tune a Windows PC for development purposes?
cletus
- 9,999
- 9
- 37
- 40
8
votes
5 answers
How to fine-tune our MySQL server?
MySQL is not my thing, yet I need to fine-tune one of our servers.
Here are the requirements/specs:
The MySQL server has only one
significant database
We only have one "type" of application connected to it, and not many instances at the same time…
Julien Genestoux
- 609
- 8
- 19
8
votes
2 answers
Tuning Linux's IPv6 stack
I'm working on a Linux network deice, and there are some TCP/IP settings that don't seem to have IPv6 equivalents. IP forwarding is a common setting, and available in both stacks
net.ipv4.ip_forward
net.ipv6.conf.all.forwarding
But these are…
JimB
- 1,924
- 12
- 15
7
votes
4 answers
Apache2 PHP Site - Hitting MaxClients limit - diagnosing?
We have a moderate-traffic site (roughly 20,000 hits a day), running a PHP/MySQL app on Apache 2.2, Ubuntu 9.10 Server, from an Amazon EC2 c1.small instance (1.7 Gb of RAM).
We had issues with the website repeatedly becoming unresponsive. As a dirty…
victorhooi
- 515
- 3
- 11
- 20
7
votes
1 answer
ext3 file system performance tuning: what metrics to monitor
I have a high-IO application that is working, and scaling well to date. Over the past few months we've been trying to look down the road and predict where our next bottlenecks will occur. One of them is surely the file system.
We are currently…
Stu Thompson
- 3,349
- 7
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- 47
6
votes
1 answer
Red Hat Linux tuning for a single application with a few TCP clients
I know Linux is built for multi-user / concurrent-process, but at the corporate level, many of them are used for single (but big) applications to support an internal service, of which serving only very few clients.
In such a use case, how should we…
steveoreo
- 61
- 2
6
votes
3 answers
Picking the right innodb_buffer_pool_size
I have a 24GB machine running MySQL (only InnoDB tables).
My innodb data set is 11.5GB big, and i have set my innodb_buffer_pool_size to 14GB to allow some growth. So the entire innodb data set is loaded into the ram, which is good.
But today i…
Mr.Boon
- 1,471
- 4
- 24
- 43
5
votes
1 answer
Nginx & Passenger - failed (11: Resource temporarily unavailable) while connecting to upstream
I have an Nginx and Passenger setup that is proving problematic.
At relatively low loads the server seems to get backed up and start churning results like this into the error.log:
connect() to unix:/passenger_helper_server failed
(11: Resource…
Toby Hede
- 309
- 5
- 11