Quick question about using kill -USR1 to recreate access.log

[Maxim Dounin]

Hello!

On Mon, May 19, 2014 at 03:06:06PM -0400, samingrassia wrote:

> Thanks to everyone in advance!
> 
> I have a cron that runs the following:
> 
> mv $NGINX_ACCESS_LOG $ACCESS_LOG_DROPBOX/$LOG_FILENAME
> kill -USR1 `cat $NGINX_PID`
> 
> My questions is during time between the mv and the kill, is there any log
> writes that are being discarded or are they being stacked in memory and
> dumped into the new access.log after it is recreated?

Unless you are trying to move logs to a different filesystem, 
logging will continue to the old file till USR1 is processed.

>From nginx point of view, the "mv" command does nothing - as nginx 
has open file descriptor, it will continue to write to it, and log 
lines will appear in the (old) file - the file which is now have a 
new name.  After USR1 nginx will reopen the log, and will continue 
further logging to a new file.

-- 
Maxim Dounin
http://nginx.org/