Questions tagged [optimization]

Optimization is the process of modifying a system to make some aspect of it work more efficiently or use fewer resources.

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46 votes
7 answers
56k views

Why rsync is faster than NFS?

Few days ago I noticed something rather odd (at least for me). I ran rsync copying the same data and deleting it afterwards to NFS mount, called /nfs_mount/TEST. This /nfs_mount/TEST is hosted/...
grs's user avatar
  • 2,235
30 votes
3 answers
79k views

Optimal values for ServerLimit, MaxClients, MaxRequestsPerChild directives

I'm running a traffic intense site plenty of dynamic content, mostly user-generated. The server is a dedicated one and has a total of 4 Intel(R) Xeon(R) CPU X3210 @ 2.13GHz proccesors. I need to know ...
andreszs's user avatar
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29 votes
5 answers
4k views

What configuration options for MySQL provide the biggest speed improvements?

What configuration options for MySQL provide the biggest speed improvements? I'm wondering about actual configuration file improvements, table types, hardware setups, replication, etc. Anything other ...
28 votes
3 answers
89k views

Maximizing rsync performance and throughput - directly-connected gigabit servers

I have two Dell R515 servers running CentOS 6.5, with one of the broadcom NICs in each directly attached to the other. I use the direct link to push backups from the main server in the pair to the ...
dyasny's user avatar
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27 votes
7 answers
12k views

Options to efficiently synchronize 1 million files with remote servers?

At a company I work for we have such a thing called "playlists" which are small files ~100-300 bytes each. There's about a million of them. About 100,000 of them get changed every hour. These ...
Zilvinas's user avatar
  • 383
27 votes
3 answers
35k views

How to determine the best byte size for the dd command

I know that doing a dd if=/dev/hda of=/dev/hdb does a deep hard drive copy. I've heard that people have been able to speed up the process by increasing the number of bytes that are read and written at ...
James T's user avatar
  • 565
25 votes
7 answers
56k views

How many files in a directory is too many? (Downloading data from net)

Greetings, I'm writing some scripts to process images from various photo websites. Right now I'm storing all this data in individual text files in the same directory. The directory is web ...
steve's user avatar
  • 535
20 votes
2 answers
13k views

IIS 7.5 optimizations for a site serving only static content

I'm looking to setup a cookie-free domain intended to serve static content for a web application, similar to the http://sstatic.net/ site that the stack exchange sites use. My question is, what ...
DanP's user avatar
  • 303
18 votes
3 answers
9k 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 ...
Ben's user avatar
  • 283
17 votes
6 answers
18k views

Optimize apache/php/mysql running on VPS for heavy load

Question about optimizing an apache/mysql server on a VPS with 512m of RAM. Under normal load everything runs fast, no connection lag. However when we get our heavy traffic days (50k+ visits) the ...
Parrots's user avatar
  • 285
15 votes
5 answers
16k views

How to minimise SpamAssassin (spamd) memory use

I'm using SpamAssassin on Debian (the default configuration with Pyzor, AWL and Bayes disabled, and sa-compile enabled), and each of the spamd child processes consume around 100 to 150MB of memory (...
Tony Meyer's user avatar
14 votes
6 answers
551 views

First days online : how not to kill your site

Suppose you have this fancy new site, with lots of data (like big images), and you're about to put it online. If you do "too much" publicity, during the first days, the site will be overwhelmed with ...
mathieu's user avatar
  • 335
14 votes
1 answer
18k views

How to disable keys in MySQL InnoDB tables?

Is it possible to disable keys in InnoDB tables? If yes, how? If not, why?
user12145's user avatar
  • 1,125
12 votes
2 answers
25k views

Nginx auto minify html output

does anyone know of a way to get nginx (or any other method) to minify html output on the fly? It seems straightforward to me and can shave a few kb off and help speed up the site.
Trazx's user avatar
  • 235
10 votes
2 answers
4k views

Linux Slow Start: Changing ip route does not have any effect on initial window

I changed the tcp initial window in my machine to 10 as shown below [user@site etc]$ sudo ip route change default via 17.255.209.1 dev eth0 proto static initcwnd 10 And changed ...
Quintin Par's user avatar
  • 4,443
10 votes
1 answer
4k views

When should you use and not use Etags?

I was just looking at our site on WebPageTest.org and one of their recommendations for speeding up a website is: ETag headers should generally not be used unless you have an explicit reason to need ...
Django Reinhardt's user avatar
10 votes
2 answers
43k views

What are typical NFS read/write rates

I have just installed a server that is sending HTTP video streaming files to a Web server over NFS and I want to make sure that I have the transfer speed optimized. But I don't know what sort of read/...
Adam Salkin's user avatar
9 votes
1 answer
1k views

How can I tell when it is time to defrag my SQLServer database?

What is the best practice for measuring SQLServer database fragmentation/performance rolloff and determining when to defrag a SQLServer database table? I'm most interested in learning what the useful ...
Jeff Leonard's user avatar
9 votes
1 answer
25k views

Apache prefork optimization - Choosing the right `MaxRequestsPerChild` value

I'm trying to optimize our web servers to handle as much connections as possible. I read a many posts and the Apache notes. I'm trying to understand which value should I choose for MaxRequestsPerChild....
Kuf's user avatar
  • 449
9 votes
2 answers
2k views

Speed up MySQL inserts with partitions on MyISAM with unique key

I have a large MyISAM table (~30M rows). At some point I've switched it to fixed row format, so now table takes ~40Gb on disk and 2Gb for indexes. Table has a unique index and there are 100 'insert on ...
d0rc's user avatar
  • 91
8 votes
6 answers
4k views

At what point is a server considered idle?

Conceptually, what is the definition of an idle server? What resource metrics would you look at to make an assumption on whether or not a server was idle? Would you look at: CPU utilization Disk ...
Johnrad's user avatar
  • 203
8 votes
4 answers
11k views

Profiling Apache+Mysql+Php server - which is the bottleneck?

How do I profile an Linux + Apache + Mysql + Php server for speed? I have a server with a heavily modified MediaWiki instance running on Ubuntu 8.04. It's a bit sluggish - I haven't done anything to ...
amarillion's user avatar
  • 1,409
8 votes
4 answers
2k views

IIS Optimization

What kind of optimization (performance or whatever) do you use when going live with IIS (on windows 2003) ? Currently, I use 1 application pool per web site, but I think I can do more :)
mathieu's user avatar
  • 335
8 votes
2 answers
18k views

Fixing window scaling problems with Linux TCP

I'm trying to improve the throughput of one of my servers overseas and after monitoring a transfer between the server and my home computer with wireshark I'm pretty sure I have a problem with the ...
incognito2's user avatar
8 votes
2 answers
1k views

what is the IOPS behavior when partitions of single disk are used in an LVM?

I have an ubuntu 14.04.1 LTS server which have LVM(backed by hardware RAID5) with logical volume and a volume group named "dbstore-lv" and "dbstore-vg" which have sdb1 sdb2 sdb3 created from same sdb ...
sherpaurgen's user avatar
7 votes
1 answer
4k views

How to select the best Stripe Size when configuring a RAID Array

There are various "references" on the Internet that delve into some discussion about what factors to consider when selecting a particular RAID stripe size (4KB to 128KB or more) for an array of disks, ...
Tall Jeff's user avatar
  • 1,673
6 votes
3 answers
57k views

Evaluating the CPU I/O wait on Linux

Doing a top to check the io wait, I get these figures: Cpu(s): 6.7%us, 1.4%sy, 1.2%ni, 85.5%id, 5.0%wa, 0.0%hi, 0.3%si, 0.0%st Looking at these figures (%us ~= %wa), do they mean that: there ...
Toto's user avatar
  • 293
6 votes
2 answers
4k views

Does it makes sense to run "optimize table" when the mysql database is stored on SSD?

The manual says about "optimize table": "Deleted rows are maintained in a linked list and subsequent INSERT operations reuse old row positions. You can use OPTIMIZE TABLE to reclaim the ...
András Szepesházi's user avatar
6 votes
1 answer
29k views

Nginx "ssl_stapling" ignored, no OCSP responder URL in the certificate

I'm trying to setup OCSP stapling on Nginx because I ran a test and it suggested the idea and well, you know. https://sslcheck.globalsign.com/en_GB/sslcheck?host=aj2jewellers.co.uk#176.58.103.165 I'...
Mark Robinson's user avatar
6 votes
3 answers
3k views

Optimizing VPS Server Memory

WHAT I'M TRYING TO DO The server resource limits sometimes run tight; to help prevent memory exhaustion, I've had to limit server processes. I'm needing a little expert help to know if I'm on the ...
Michael's user avatar
  • 81
6 votes
5 answers
11k views

CPU's on Hyper-V host system is just idling, even though VM's are at full throttle

I have a server that is running Windows 2008 64 bit Hyper-V, with 8 gigs of RAM and Intel Xeon X3440 @ 2.53 Ghz, which gives me 8 logical cores in the performance monitor on the host system. I have ...
Bjørn's user avatar
  • 337
6 votes
2 answers
539 views

Do you remove unwanted packages (*NIX), or do you disable them?

Im currently building a cobbler and puppet setup. One thing I do is disabling unwanted services with puppet, but then I thought: Should I remove them with cobbler, rather than disabling them after ...
tore-'s user avatar
  • 1,396
6 votes
3 answers
4k views

Guest optimization tips for Ubuntu on VirtualBox [closed]

I was wondering if anyone could shed light into "Guest optimization tips for Ubuntu (guest)" I came across Virtual Machine guest optimization tips, for Windows. (serverfault.com/questions/4647/ubuntu-...
Mak's user avatar
  • 173
6 votes
1 answer
476 views

Red Hat Linux tuning for a single application with a few TCP clients [closed]

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 ...
steveoreo's user avatar
6 votes
3 answers
5k views

Can I optimize these APC settings more?

I would like to optimize APC some more but I am not sure where I could do something. First here is the screenshot after one week of running with the current configuration: I have now the following ...
Raffael Luthiger's user avatar
6 votes
3 answers
2k views

Very slow write speed (NVME drive) on 10G network

Setting up an experimental lab cluster, the write speed for data received via 10G fiber connection is 10% of the local write speeds. Testing transfer speed between two identical machines; iperf3 shows ...
roman's user avatar
  • 191
6 votes
2 answers
2k views

Cron job for database repair and optimization

I would like to repair + optimize my MySQL database once a week! How could I do this?
Chris wede's user avatar
6 votes
1 answer
4k views

Nginx performance when running multiple instances on the same machine

I'm trying to understand the performance impact of having multiple nginx instances (masters) running on the same machine, rather than having them all load into a single instance using different server ...
eddiemoya's user avatar
  • 167
6 votes
2 answers
4k views

How can I determine the memory used by a forked process (Linux)?

Following on from this question. Debian, if that matters. I understand that some memory is shared between forked processes. How then can I determine how much memory is used by a process/set of ...
Tony Meyer's user avatar
5 votes
6 answers
3k views

Method for finding unnecessary indexes of an operational SQL Server database?

Besides wasting space on the database, unnecessary indexes on SQL Server can slow down insert and update operations. Developers who lack experience in database principles sometimes tend to create ...
splattne's user avatar
  • 28.6k
5 votes
6 answers
684 views

Capacity Optimization / Deduplication Options for Primary Storage

I'm exploring options for making more efficient use of our primary storage. Our current NAS is an HP ProLiant DL380 G5 with an HP Storageworks MSA20, and one other disk shelf which I'm not sure what ...
Stephen Denne's user avatar
5 votes
2 answers
2k views

How can I handle big traffic spikes on my dedicated server?

I have an E-Commerce site, which gains a sudden peak of very high traffic when I turn on different ads campaigns. From this moment on, my current dedicated server (Hostgator, 4GB Memoray, 100mbps ...
aceph ali's user avatar
5 votes
2 answers
8k views

Disk I/O utilization up to 100% after tuning InnoDB-related MySQL configuration

I have added following lines to "my.conf": query_cache_size=128M innodb_buffer_pool_size=512M innodb_flush_method=O_DIRECT After that Disk utilization started raising, reached 100% and holds steady, ...
spacemonkey's user avatar
5 votes
2 answers
2k views

How do I optimize TCP stack for HTTP server?

I have a HTTP server that serves only two kinds of page: about 10 KB and about 16 KB (both compressed, other files are from CDN). As the latency is quite high (ping takes more than 300 ms), I want to ...
jcisio's user avatar
  • 586
5 votes
2 answers
5k views

Optimizing MySQL for small VPS

I'm trying to optimize my MySQL config for a verrry small VPS. The VPS is also running NGINX/PHP-FPM and Magento; all with a limit of 250MB of RAM. This is an output of MySQL Tuner... -------- ...
Chris McKee's user avatar
  • 3,539
5 votes
0 answers
2k views

`nginx reload` and `nginx -t` very slow - how to investigate

I have a quite small VPS on AWS (EC2 t2.nano) that is running an nginx server. while sometimes a sudo service nginx reload or nginx -t is blazing fast, most of the time it is horribly slow (>60 ...
Tobi's user avatar
  • 257
5 votes
2 answers
6k views

Optimize php-fpm and varnish for a powerful server

My setup is Intel® Core™ i7-2600 and RAM 16 GB DDR3 RAM varnish+nginx+php-fpm+apc for a not very heavy WordPress blog with W3 Total Cache and CDN My problem is that after 55 hits per second ...
Jim's user avatar
  • 410
4 votes
5 answers
32k views

How to Best Manage High PostgreSQL CPU Use?

I am trying to fix a high PostgreSQL CPU use problem. We are using PostgreSQL 8.0.9 and when our JEE web application (in JBoss) is used in certain load increase conditions, top shows a slow increase ...
user75452's user avatar
  • 111
4 votes
2 answers
5k views

Do access logs (from nginx) slow down a website?

Does it slow down a website if your webserver (in my case, nginx) is writing to an access log? I'm mostly wondering if it's noticeable. Plus, what's the point of knowing the user agents / ips that ...
Matthew's user avatar
  • 1,917
4 votes
8 answers
6k views

Optimize a fresh Ubuntu server installation

After installing a fresh Ubuntu server (I personally use 8.04 LTS) what do you do to optimize it in terms of memory consumption, disk usage and speed? What services and pre-installed packages do you ...
Luke's user avatar
  • 3,846

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