It’s just a mirror script and all but there is still a chance of having a race condition when using a pid/locking system like that.  I used to do it the same way until recently I discovered a utility called flock.  You can either use it within your script or you could simply use a one liner in your crontab.  I’ve included examples both ways.  flock is provided by util-linux package
 
Here’s one way via CRON
0 */6 * * * /usr/bin/flock -x -w 0 200 -c '/usr/bin/rsync -azH --delete --delay-updates –stats --no-motd msync.centos.org::CentOS /mirror/centos' 200>/var/lock/centos_mirror_sync
 
And here’s the way I do with with a script, my cron entry looks like the following...
 
0 */6 * * * /sbin/centos_mirror_sync >> /var/log/centos_mirror_sync.log 2>&1
 
The script is at http://mirrors.ndchost.com/ndchost/scripts/rsync_mirror_script
 
The script names the lock file after whatever you name the script, so if you rename the script to centos_mirror_sync and have another copy named debian_mirror_sync they should not conflict with each other.
 
--
Shaun Reitan
Network Data Center Host, Inc.
www.ndchost.com
 
Sent: Thursday, February 28, 2013 11:11 AM
Subject: Re: [CentOS-mirror] setup mirror and lock files
 

Sure thing, I'm not at the office right now but when I am I'll send it off to you.

On Feb 28, 2013 1:02 PM, "Tony Schliesser" <tony@schliesser.org> wrote:
Ryan - If you don't care to share your mirror script, I'd like to see it.
 
Thanks,
Tony
 
 
Hi Jim, it's quite easy to do with a script. This first section here checks to see if a lock is present, and if it is, the script bails:
 
if [ -f /var/lock/subsys/rsync_updates ]; then
    echo "Updates via rsync already running."
    echo "--ERROR: REPOSITORY SYNC ABORTED AT `date`--"
    exit 0
fi
 
When I begin my sync, it touches the lock file (touch /var/lock/subsys/rsync_updates), and when finished, removes it (/bin/rm -f /var/lock/subsys/rsync_updates). If you need any help or wish to see my full script, just let me know and I can provide it.
 


On Wed, Feb 27, 2013 at 8:42 PM, Jim Hartnett <mirrors@gawsolutions.us> wrote:
Ok, I have the lock scripts setup and working, I think we're ready to
add our mirror.

(information repeated):

mirror Url: http://mirrors.gawsolutions.us/centos
bandwidth: 100 Mbps up/down unmetered transfer
located in dallas, tx, usa
Geeks at Work Solutions
centos machine with apache
rsync twice a day at offset minutes (reduces peak for even hour starts)

- -Jim

P.S: sorry if this message gets repeated multiple times. I just found out my email client was having some issues with the account I use for mirror mailing lists

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