crond/anacron

[Patrick Dupre]

Hello,

I am trouble because I guess that crond and anacron
run are very close times.
Hence, they start a backup when another backup is running.
This creates real problems.

What do you recommend?
Running only crond or only anacron?
Usually, this machine runs every day for at least 1-2 hours
durin the week, and a long loner during the week-end (when backuo
is run).
However, it may happen that the machine is not run during several weeks.

Thanks.

===========================================================================
 Patrick DUPRÉ                                 | | email: pdupre(a)gmx.com
 Laboratoire interdisciplinaire Carnot de Bourgogne
 9 Avenue Alain Savary, BP 47870, 21078 DIJON Cedex FRANCE
 Tel: [phone]                    | | Room# D114A
===========================================================================

[Ed Greshko]

On 11/12/2021 22:02, Patrick Dupre wrote:
>  I am trouble because I guess that crond and anacron
>  run are very close times.
>  Hence, they start a backup when another backup is running.
>  This creates real problems.
>
>  What do you recommend? 
Are you using your own scripts to perform the backups?

If so, the easy solution would be for the script to check for a "lock file" to
see if another backup is running.  If no "lock file"
exists, then create one to prevent a second backup from starting and then clearing the
"lock file" after the backup is
finished.


--
Did 황준호 die?

Hi

On Sat, 11 Dec 2021 23:28:20 +0800 Ed Greshko wrote:

>  Are you using your own scripts to perform the backups? 
>  If so, the easy solution would be for the script to check for a
> "lock file" to
>  see if another backup is running. ... 
Even easier is to use a systemd service and timer (system or user) to start this
backup: this will do this locking for you.

> > Usually, this machine runs every day for at least 1-2 hours durin
> the week,
> > and a long loner during the week-end (when backuo is run). 
> > However, it may happen that the machine is not run during several
> weeks. 
For example, if you only want a backup per day, run this timer every hour but
instrument your script to do nothing if a backup has been done less than 24 hours
ago.

-- 
francis

[Ed Greshko]

On 11/12/2021 23:48, Francis.Montagnac(a)inria.fr wrote:
>  Even easier is to use a systemd service and timer (system or user) to
> start this
>  backup: this will do this locking for you. 
Needless to say, you are correct.  Need to rewire my old-school brain.

--
Did 황준호 die?

[Jonathan Billings]

On Dec 11, 2021, at 09:03, Patrick Dupre <pdupre(a)gmx.com&gt; wrote:
>  
>  I am trouble because I guess that crond and anacron
>  run are very close times.
>  Hence, they start a backup when another backup is running.
>  This creates real problems.
>  
>  What do you recommend?
>  Running only crond or only anacron?
>  Usually, this machine runs every day for at least 1-2 hours
>  durin the week, and a long loner during the week-end (when backuo
>  is run).
>  However, it may happen that the machine is not run during several weeks. 
Anacron is a dependency for cronie (the cron daemon) and is normally enabled.  In your
case, most likely it is just running the /etc/cron.daily or /etc/cron.weekly jobs you have
defined, when you boot your system.  

The thing is, Anacron only runs if you boot after the scheduled job is supposed to run out
of cron.  It shouldn’t run twice.  So maybe you have your backups scheduled in more than
one place?

Anyway, I agree with the others, use a lock file to prevent running simultaneous backup
jobs. There are ways to do this with simple shell logic, with the “dotlockfile”
executable.

—
Jonathan Billings

[Jonathan Billings]

>  On Dec 11, 2021, at 10:38, Jonathan Billings
> <billings(a)negate.org&gt; wrote:
>  
>  The thing is, Anacron only runs if you boot after the scheduled job is supposed to run
> out of cron.  It shouldn’t run twice.  So maybe you have your backups scheduled in more
> than one place? 
I should be extra clear here - Anacron is what runs the cron.daily (and weekly, monthly)
jobs.  They just will also run shortly after boot on the hour if you boot later in the
day.  Disabling Anacron will break the cron.daily, cron.weekly, cron.monthly jobs.

So there’s no way they’d run twice unless you have it in more than one scheduling
service/location.

—
Jonathan Billings

[Patrick Dupre]

Hello,

Thank for all the comments.
The issue is with weekly cron
On Saturday, /etc/cron.weekly/backup.cron is run twice

Here is /etc/anacrontab
#period in days   delay in minutes   job-identifier   command
1	5	cron.daily		nice run-parts /etc/cron.daily
7	25	cron.weekly		nice run-parts /etc/cron.weekly
@monthly 45	cron.monthly		nice run-parts /etc/cron.monthly

and here /etc/crontab
22 23 * * * root run-parts /etc/cron.daily
30 12 * * 6 root run-parts /etc/cron.weekly

I understand that if I set
dotlockfile -l
at the beginning of my /etc/cron.weekly/backup.cron
and
dotlockfile -u
at the end of the same file
I must avoid to run 
/etc/cron.weekly/backup.cron
at the same time, but it does not prevent to run
/etc/cron.weekly/backup.cron twice (sequentially) in the same day (like today).


===========================================================================
 Patrick DUPRÉ                                 | | email: pdupre(a)gmx.com
 Laboratoire interdisciplinaire Carnot de Bourgogne
 9 Avenue Alain Savary, BP 47870, 21078 DIJON Cedex FRANCE
 Tel: [phone]                    | | Room# D114A
===========================================================================


> Sent: Saturday, December 11, 2021 at 5:08 PM
> From: "Jonathan Billings" <billings(a)negate.org&gt;
> To: "Community support for Fedora users"
<users(a)lists.fedoraproject.org&gt;
> Subject: Re: crond/anacron
>
> 
> 
> > On Dec 11, 2021, at 10:38, Jonathan Billings <billings(a)negate.org&gt; wrote:
> > 
> > The thing is, Anacron only runs if you boot after the scheduled job is supposed
to run out of cron.  It shouldn’t run twice.  So maybe you have your backups scheduled in
more than one place?
> 
> I should be extra clear here - Anacron is what runs the cron.daily (and weekly,
monthly) jobs.  They just will also run shortly after boot on the hour if you boot later
in the day.  Disabling Anacron will break the cron.daily, cron.weekly, cron.monthly jobs.
> 
> So there’s no way they’d run twice unless you have it in more than one scheduling
service/location.
> 
> —
> Jonathan Billings
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[Ed Greshko]

On 12/12/2021 02:44, Patrick Dupre wrote:
>  Thank for all the comments. 
Francis Montagnac had the best suggestion.

--
Did 황준호 die?

[Jonathan Billings]

>  On Dec 11, 2021, at 13:45, Patrick Dupre <pdupre(a)gmx.com&gt;
> wrote:
>  
>  and here /etc/crontab
>  22 23 * * * root run-parts /etc/cron.daily
>  30 12 * * 6 root run-parts /etc/cron.weekly 
Ah. This is why you are getting two jobs. /etc/crontab should not have those two lines.
There should be an /etc/cron.hourly/0anacron that calls anacron. The anacron job calls
cron.daily and cron.weekly from /etc/anacrontab. 

That’s why you have two jobs running. They’re both running through cron.daily and
cron.weekly twice. 


I suspect either you added those lines at some point or the system had it at some time in
the distant path and you’ve been upgrading for so long it got dragged along with it. 

Just remove those lines from /etc/crontab and you’ll be good to go. 

--
Jonathan Billings