Questions tagged [optimization]

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

A system may be optimized so that it executes more rapidly, or is capable of operating with less memory storage or other resources, or draw less power. The optimized system will typically only be optimal in one application or for one audience. For example, one might reduce the amount of time a task takes to perform at the price of making it consume more memory.

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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/write rates are typical so I don't know if I…
Adam Salkin
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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 them I was wondering what this means. Does it…
Django Reinhardt
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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 metrics are and what level of performance…
Jeff Leonard
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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. At first, I've tried setting it to 4,000, but…
Kuf
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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 duplicate key update' queries per second. As…
d0rc
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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 disk. The system as 42 cores and about 128G…
sherpaurgen
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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 Usage Memory Usage If so, what thresholds would…
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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
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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 optimize it yet so I'm sure there is plenty of…
amarillion
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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 window size. For an ftp transfer I get a receive…
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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, but none of these come across as very…
Tall Jeff
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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 blocks. How does the use of multiple instances…
eddiemoya
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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
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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 are almost as many CPU processes waiting than…
Toto
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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'm getting the error: nginx: [warn] "ssl_stapling"…
Mark Robinson
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