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Why is my system slow?

This is not a performance tuning article. If your system is always slow, this article may not be what you are looking for. I'll be covering some general performance related issues here, but the main focus is for the system that was running fine yesterday but is sucking mud today. The typical response to such problems is "Reboot it", and while that may indeed fix the problem, it does not address the root cause, so you are likely to have the situation again.

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Clicky Analytics for your website  
- Clicky Analytics offers some advantages over Google Analytics and can be used alongside too. -

More about Cloudflare  
- CloudFlare should now be fully active on this site. Visitors should only see speedups in page loads and no adverse affects. -

SCO Unix Performance Tuning  
- People who are stuck running legacy SCO Unix systems may find these tips useful. -

Why defragging your computer may be a waste of time   2012/12/03 BigDumbDinosaur
- In fact, defragmenting may be a total waste of time. It's unlikely to be harmful (though it can be if interrupted by a sudden power failure), but it may actually accomplish nothing worth even the minor effort it takes to run it. -

(SCO Unix)Why is ftp transfer between two 100Mb machines so slow?  
- Usually this sort of thing is from bad (cheap) Nic cards and/or mis-negotiation with the switch or just lousy drivers. Ftp does a lot of work; junk affects it more than simple http, telnet or ssh connections. -

Windows Performance Boosts  
- This is about speeding up your Windows computer. I'm assuming that you have sufficient disk space, RAM and that you don't have viruses or spyware running . -

CPU sucking processes  
- Slowness can come from many causes and you really need to identify WHY a system is slow before throwing fixes at it -

- A Linux performance monitor: Collectl is rather well described at http://collectl.sourceforge.net. I have only just started playing with it, but it does seem worth looking at. -

msie701.exe slows machine  
- Slow Windows caused by spyware trojan? I initiated a 'chat' session with a representative from Earthlink, and got the usual 'We don't support Linux' line. -

Solaris Performance Tools  
- I'm not as fascinated by tuning as I used to be. Nevertheless, this was an interesting read. I did not know, Most of this book is about Dtrace (Sun's Dynamic Tracing Tool) and -

Where's the memory?  
- Memory usage under Linux is full of surprises. Do not assume you know what's going on based upon your knowledge of other systems. -

Cost of Performance  
- Predicting and controlling performance costs may seem overwhelming to many organizations. -

Server Load - The Basics   2012/11/27 TonyLawrence
- Server load averages display in "w". In a *Nix variant, Server load can be calculated by the uptime or the w command. -

Optimizing Linux Performance  
- I found a lot to like here, but I do need to complain about a few things. -

Performance Tuning for Linux Servers  
- I'm trying hard to like this more than I do. It's not that there isn't good stuff in here; there is. But I just can't get excited about it. -

sysstat (iostat,mpstat,sar): Tech Words the Day  
- When I mention this to Linux folk, the first reaction is usually "What do I need that for? It's all in /proc!". Well, that's not really the point. -

Sarcheck for Linux  
- On traditional Unix systems, Sarcheck analyzes data produced by "sar", but Linux systems don't usually have sar. It is available as part of the sysstat package on RedHat, and I do recommend that you install sysstat if you can, but Sarcheck on Linux installs its own data collection tools. -

External SATA drives  
- In theory, at least, multiple SATA disks have higher throughput than multiple SCSI drives because they aren't sharing a bus. -

Cartoons: Bad Dreams  
- Profiled, optimized, stripped - I'm the fastest program in this memory block -

LOD Communications, Inc.
amird driver, BDFLUSH and NAUTOUP, and more  
- New, very fast RAID controller, burt the customer say it is slower! Why? BDFLUSH and NAUTOUP are the culprints. -

Sendmail Performance Tuning by Nick Christensen  
- When I first picked this up I really didn't expect much. I expected that this would be a rather ordinary rehash of typical performance tuning advice -

Why is my system slow?   2010/06/11 veera
- This is not a performance tuning article. If your Linux or Unix system is always slow, this article may not be what you are looking for. -

Linux|Unix Performance Tuning and Capacity Planning  
- Strangely, there's a review of this at Amazon that complains about the book being too general, not Linux specific. In fact, it is very Linux specific. -

General Trouble Shooting   2010/12/24 anonymous
- Sometimes computer problems can feel like Dickens' dying woman- you know something is wrong, but you have no idea where or how to start looking for it. -

- Using sarcheck to analyze sar reports. Unfortunately, tuning a computer is not like tuning a car (or maybe it is, if you are thinking of high performance racing tuning). It's complex: what looks like a CPU problem can really be -

High Performance Computing  
- Is a Pentium 200 a high performance computer? Certainly if you compare it to 1970's computing, it is. In fact, the small computers of today have many of the features of yesterdays supercomputers. The Pentium Pro CPU, for example, is really a RISC design with pipelining, out of order execution and speculative execution: features that only a few years back were found only in extremely expensive systems. -

Adding Memory  
- Adding Memory to SCO Unix, tuning NBUF and NHBUF to use that RAM -

DPT Raid Controller  
- DPT ( http://www.dpt.com) builds a complete line of SCSI raid controllers -

Web Performance Tuning  
- Still, because this concentrates on web performance, the specific concentration is valuable. There is a very good section that explains tcp kernel parameters (it tells you that "ndd" is the tool that modifies these; on SCO it's "inconfig"), there is a good section on cgi, a lot of Java specific tips and so on. -

Configuration and Capacity Planning  
- There is a strong concentration and many pages devoted to NFS, and that may not be of great interest to many of us. You should read those parts anyway; there is a lot of general network knowledge mixed in,0 -

(SCO Unix)How to setup resolv.conf for DNS configuration   2010/05/24 alexB
- (SCO Unix) Reverse lookups (lookup name from ip) happen for every attempted connection. Edit the resolver file to get proper behavior and quicker connections. For Linux,that's /etc/host.conf; most other Unixes use /etc/resolv.conf -

(SCO Unix)User login hangs for many seconds before password prompt comes up  
- (SCO Unix) User login hangs can be caused by reverse DNS lookups - this is true for Unix, Linux and Windows. -

(SCO Unix)Why do I get vhand spinning ?  
- This is an old article about a "vhand spinning" error on SCO Unix and is only left here for historical purposes. -

(SCO Unix)How do I get better UUCP throughput?  
- This is an old article about UUCP throughput on SCO Unix and is only left here for historical purposes. -

(SCO Unix)My system is slow or hangs when sizing memory  
- This is an old article about memory caching on SCO Unix and is only left here for historical purposes. -

(SCO Unix)How can I get the value of autotuned configuration variables?  
- (SCO Unix) How can I get the value of autotuned configurationvariables? -

(SCO Unix)My system is slow  
- SCO Unix performance tuning: This is a very old article and has little relevance to modern systems. It does remain true that having insufficient memory will cause bad performance but "tuning" is very unusual because most sytems dynamically tune now and do a very good job of it. -

lpd slow -->Re Problem with lpd going 'out to lunch'when JetDirect printer is not ready.  
- lpd slow -->Re: Problem with lpd going 'out to lunch'when JetDirect printer is not ready. -

performance slow ami raid amird -->Re PerformanceDegradation on New Hardware Platform  
- performance slow ami raid amird -->Re: PerformanceDegradation on New Hardware Platform -

Linux parallel port slow -->Re Printer Settings?  
- Linux parallel port slow -->Re: Printer Settings? -

login slow dns setup -->Re Login prompt veryslow  
- login slow dns setup -->Re: Login prompt veryslow -

Program reacts slowly to ESCAPE key -->Re Please help with Response Time and Screen Views  
- ESCAPE key not functioning or functioning very slowly.0 -

cpu cache explained -->Re 5.0.5 MP system running slowly with 1Gb RAM  
- Explaining cache design vs. memory amount cached. There is no linear relationship between size of cache and amount of RAM it can cache. This is a common misconception. -