Cron'd rsync process out of control.

ghostmac · 11-12-2008, 09:18 PM

Greetings Gurus,
My desktop machine is a 64 bit version of Ubuntu 8.04.1, 2.6.24-21 kernel and using rsync version 2.6.9 protocol version 29.

I recently added a 1Tb drive to the setup (XFS) to handle backups.
I tossed the rsync command;

Code:

rsync -avh --progress --delete --exclude-from=/root/.rsync/exclude /home /media/sdc1/

into a file and scheduled it to run once a day at 5am via;

Code:

# m h  dom mon dow   command
* 5 * * * /root/.rsync/.homes_sync>/dev/null 2>&1

.
Everything seems to work fine though once in a while (once every two weeks or so), I'll wake up and there will be +30 instances of rsync running bogging down the system.
I look at my logs and;

Code:

Nov 12 05:00:01 Balius /USR/SBIN/CRON[18858]: (root) CMD (/root/.rsync/.homes_sync>/dev/null 2>&1)
Nov 12 05:01:02 Balius /USR/SBIN/CRON[21872]: (root) CMD (/root/.rsync/.homes_sync>/dev/null 2>&1)
Nov 12 05:02:02 Balius /USR/SBIN/CRON[24874]: (root) CMD (/root/.rsync/.homes_sync>/dev/null 2>&1)
Nov 12 05:03:02 Balius /USR/SBIN/CRON[27890]: (root) CMD (/root/.rsync/.homes_sync>/dev/null 2>&1)
Nov 12 05:04:02 Balius /USR/SBIN/CRON[30920]: (root) CMD (/root/.rsync/.homes_sync>/dev/null 2>&1)
Nov 12 05:05:02 Balius /USR/SBIN/CRON[1464]: (root) CMD (/root/.rsync/.homes_sync>/dev/null 2>&1)
Nov 12 05:06:02 Balius /USR/SBIN/CRON[4488]: (root) CMD (/root/.rsync/.homes_sync>/dev/null 2>&1)
Nov 12 05:07:07 Balius /USR/SBIN/CRON[7678]: (root) CMD (/root/.rsync/.homes_sync>/dev/null 2>&1)
Nov 12 05:08:01 Balius /USR/SBIN/CRON[10693]: (root) CMD (/root/.rsync/.homes_sync>/dev/null 2>&1)
Nov 12 05:09:11 Balius /USR/SBIN/CRON[13718]: (root) CMD (/root/.rsync/.homes_sync>/dev/null 2>&1)

. . . .and so on until 5:59am.

My question is A.Is my job not scheduled correctly and B.If it is, why does this only happen once in a while?

I would think that if the scheduling is incorrect, it may run every 5 hours or every 5 min, but once a min for an hour?

My apologies if this is obvious.

AuroraCA · 11-12-2008, 09:28 PM

If you notice that you have your crontab set to run every minute from 5:00 a.m.

Code:

# m h  dom mon dow   command
* 5 * * * /root/.rsync/.homes_sync>/dev/null 2>&1

The * in the minute specification runs every minute during the 5 o'clock hour.

If you want to execute your command once you must specify a single time such as:

Code:

# m h  dom mon dow   command
0 5 * * * /root/.rsync/.homes_sync>/dev/null 2>&1

This will run your command only once at 5:00 a.m. daily.

Code:

# m h  dom mon dow   command
30 5 * * * /root/.rsync/.homes_sync>/dev/null 2>&1

This will run your command only once at 5:30 a.m. daily.

ghostmac · 11-12-2008, 09:30 PM

Thanks!
I've edited the cron entry hopefully that'll be the end of it.