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  #1  
Old 11-04-2008, 10:51 AM
anewday anewday is offline
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Lightbulb async io & writeav setting

Will litespeed add support for async io or writeav? I heard these lower iowait when serving huge static files. This is the case on an inferior server running lighttpd, the iowait is much lower than on a higher end server running litespeed enterprise.

Last edited by anewday; 11-04-2008 at 11:17 AM..
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  #2  
Old 11-04-2008, 01:46 PM
mistwang mistwang is offline
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using async I/O is on our radar.

Async I/O make the kernel schedule tasks in a more orderly manner, so it leads to lower load, however, it does not mean it is faster. In most cases the server is disk bounded when async I/O benefits.
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  #3  
Old 11-04-2008, 04:44 PM
anewday anewday is offline
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That's great to know.

Today, I had to use my friend's server, running on lighttpd to serve the huge multimedia files because the iowait was really high and made my forum really slow. I was surprised that his server handled it fine with only 25% of my server's memory and load was well under 1. He said it's due to async io and I said why don't I suggest this to George.
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  #4  
Old 11-05-2008, 07:53 AM
mistwang mistwang is offline
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When a server performance is disk bound, async I/O will help a lot, as normally disk operation will block the single thread server process.
We currently suggest a multi-CPU license for this kind situation.
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  #5  
Old 11-05-2008, 01:55 PM
anewday anewday is offline
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So, more cpu is better to server large static files?
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  #6  
Old 11-06-2008, 02:51 AM
IrPr IrPr is offline
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Quote:
Originally Posted by anewday View Post
So, more cpu is better to server large static files?
Yes, but more CPUs with a webserver which supports SMP such as LS not lighttpd or nginx or tux which are single threaded webservers

the advantage of Litespeed is SMP support which leads to more IO handling power on multi CPU cores

Edit: nginx supports SMP and HTT as well as litespeed does!

Last edited by IrPr; 11-07-2008 at 01:27 AM..
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  #7  
Old 11-06-2008, 08:29 AM
anewday anewday is offline
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Isn't serving static files more hdd, memory bound than CPU?
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  #8  
Old 11-06-2008, 09:47 AM
mistwang mistwang is offline
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Quote:
Originally Posted by anewday View Post
Isn't serving static files more hdd, memory bound than CPU?
Yes, when the total size of static files being actively served are too large to be cached by the kernel.
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  #9  
Old 11-06-2008, 12:10 PM
zellster zellster is offline
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To be fair, nginx does support multiple worker processes.
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  #10  
Old 11-07-2008, 01:25 AM
IrPr IrPr is offline
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Quote:
Originally Posted by zellster View Post
To be fair, nginx does support multiple worker processes.
Great! i thought it does not
checked their wiki and find out thats awesome features! seems it has more stability with higher performances at least for statistic files toward lighty or maybe LS but PHP/RUBBY dynamic scripts

I've planned to port my major DL server with huge large files which pushes upto 600Mbit/s and 300Mbit avg to nginx and may do some benchmark stuffs to compare lighty, litespeed and nginx

Thanks for correction

Last edited by IrPr; 11-07-2008 at 08:56 AM..
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