question about access_log buffer size

[Igor Sysoev]

On Thu, Feb 25, 2010 at 01:16:04PM +0800, yong xue wrote:

> The *access_log* directive sets the path, format and buffer size for the
> access log file. Using "off" as the only parameter clears all
> *access_log* directives
> for the current level. If the format is not indicated, it defaults to
> "combined" <http://wiki.nginx.org/NginxHttpLogModule#log_format_combined>.
> The size of buffer must not exceed the size of the atomic record for writing
> into the disk file. This size is not limited for FreeBSD 3.0-6.0.
> 
> this is quoted from wiki.nginx.org.
> My server is running linux 2.6.16.
> I dont know the size of the atomic record for writing into the disk file.
> Can somebody help me?
> 
> I googled, but cannot make sure that  the linux write system call is atomic.

Linux shell ensure atomic write for PIP_BUF, i.e. 4K. However, I believe
this value is much more for regular files, so you may try to set 32k.


-- 
Igor Sysoev
http://sysoev.ru/en/