Question about access_log buffer size

Server NGINX
1

hi,all

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.

–
Best Regards,

薛 勇

QQ:312200

e-mail:[email protected] [email protected]

2

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

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 S.
http://sysoev.ru/en/

3

2010/2/25 Igor S. [email protected]

into the disk file. This size is not limited for FreeBSD 3.0-6.0.
this value is much more for regular files, so you may try to set 32k.

thanks.

so the size depends on the implementation. And the access log is not
much
serious.
I will do some reading on the kernel later if i have time.

–
Best Regards,

薛 勇

QQ:312200

e-mail:[email protected] [email protected]
MSN:[email protected] [email protected]