HDD util is 100% - aio questions

Lukas Tribus luky-37 at hotmail.com
Mon Jan 28 09:34:37 UTC 2013

AIO will not work with the streaming module:


On Linux, directio can only be used for reading blocks that are aligned on 512-byte boundaries (or 4K for XFS). Reading of unaligned file’s end is still made in blocking mode. The same holds true for byte range requests, and for FLV requests not from the beginning of a file: reading of unaligned data at the beginning and end of a file will be blocking. There is no need to turn off sendfile explicitly as it is turned off automatically when directio is used.

What is your exact configuration? What OS do you use, what load and what disk and RAM configuration do you have?

> From: crirus at gmail.com 
> Date: Mon, 28 Jan 2013 08:53:52 +0200 
> Subject: HDD util is 100% - aio questions 
> To: nginx at nginx.org 
> Hello 
> Right now nginx manages to put hdds in the server to high util rate. 
> I try to run Nginx 1.2.3 with aio support to deliver mp4 videos with 
> the streaming module. 
> I compiled the server with aio and it starts fine. 
> In config I set it like this 
> sendfile off; 
> output_buffers 1 2m; 
> #sndbuf=32K; 
> aio on; 
> directio 512; 
> I read that sendfile should be off, but it won't send video unless I 
> turn it on. 
> In this case does aio work at all? How can I tell, before I wait a week 
> and see that maybe HDD util is not 100% all the time anymore :P 
> --------------------------------------------------------------- 
> Cristian Rusu 
> Web Developement & Electronic Publishing 
> ====== 
> Crilance.com 
> Crilance.blogspot.com<http://Crilance.blogspot.com> 
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