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#1 2014-03-01 04:24:57

yjcong
Member
Registered: 2009-07-06
Posts: 59

[SOLVED]"at" does not work anymore

hi,

I have forgot what I did. "at" command has stopped working since yesterday, and I totally have no clue what I should do to fix it.  There are new things I have found:

1)Everytime, after turning on the power and loginning, I notice a high cpu usage(60%-80%) by "atd"

2) "at -c" returns nothing, and these jobs have never been done

3)

warning: commands will be executed using /bin/sh
job 1 at Sat Mar  1 12:14:00 2014
warning: commands will be executed using /bin/sh
Cannot create atjob file /var/spool/atd/a0000101626c3e: File exists

4)Those are job which I typed from different time. But all of them have the same ID

1	Sat Mar  1 12:05:00 2014 a yjc
1	Sat Mar  1 12:14:00 2014 = yjc
1	Sat Mar  1 12:14:00 2014 a yjc
1	Sat Mar  1 12:05:00 2014 = yjc
1	Sat Mar  1 12:12:00 2014 = yjc
1	Sat Mar  1 12:12:00 2014 a yjc


Thanks for the help.

Last edited by yjcong (2014-03-01 09:36:01)

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#2 2014-03-01 06:41:46

DaveCode
Member
Registered: 2008-08-15
Posts: 103

Re: [SOLVED]"at" does not work anymore

The lovely at package saved me twice now, getting systemd to reboot a PC and launching wineserver decently on user X login.

All I can do is guess but high CPU smells like disk I/O with errors. My thought is spool thrashing or corrupt filesys. BACKUP esp. if you have lots of e-mail in spool. Then for a bypass test run at from tmpfs. What you do is:

/etc/fstab

tmpfs /tmp         tmpfs  rw,nosuid,exec,noatime,size=800M,nr_inodes=80k  0  0
tmpfs /run         tmpfs  defaults,noatime,size=40M   0  0
tmpfs /media       tmpfs  defaults,noatime,size=10M   0  0
tmpfs /var/log     tmpfs  defaults,noatime,size=50M   0  0
tmpfs /var/cache   tmpfs  defaults,noatime,size=150M  0  0
tmpfs /var/spool   tmpfs  defaults,noatime,size=40M   0  0
tmpfs /var/tmp     tmpfs  defaults,noatime,size=10M   0  0

Edit to taste, but keep at least the /var/spool line for at.
Then do

/etc/tmpfiles.d/spool.conf

d /var/spool/mail                 1777   root    root    1d
d /var/spool/atd                  1770   daemon  daemon  1d
f /var/spool/atd/.SEQ             0600   daemon  daemon  -
d /var/spool/incron               0755   incron  incron  1d

Delete incron if you don't have it.
Reboot and see what happens. If at works, I think it's safe to conclude "disk problems."

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#3 2014-03-01 07:41:20

yjcong
Member
Registered: 2009-07-06
Posts: 59

Re: [SOLVED]"at" does not work anymore

DaveCode wrote:

The lovely at package saved me twice now, getting systemd to reboot a PC and launching wineserver decently on user X login.

All I can do is guess but high CPU smells like disk I/O with errors. My thought is spool thrashing or corrupt filesys. BACKUP esp. if you have lots of e-mail in spool. Then for a bypass test run at from tmpfs. What you do is:

Thank you.

But I am a little bit confused.

there is nothing in /etc/tmpfiles.d/

/etc/fstab

UUID=fb94e9da-143a-4682-816f-259eb1daf22f  /      ext4       defaults,noatime   0   1
UUID=71fa21e7-3f42-46c0-b7a5-08fc8c8da4f6  /boot   ext2      defaults,noatime   0    0
UUID=c1953a96-4cd8-429f-ace7-19daa9522be3 none     swap      defaults            0   0
UUID=eb6172b6-baf8-4b6b-877e-a780e9c0a12f /home  reiserfs    defaults,noatime   0 

df -h

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1       9.7G  9.2G     0 100% /
dev             751M     0  751M   0% /dev
run             753M  712K  752M   1% /run
tmpfs           753M   12K  753M   1% /dev/shm
tmpfs           753M     0  753M   0% /sys/fs/cgroup
tmpfs           753M  468K  752M   1% /tmp
/dev/sda4       304M   34M  255M  12% /boot
/dev/sda5        19G   17G  1.8G  91% /home

/var/spool# du -s -BM *

1M	anacron
1M	atd
1M	cron
1M	mail

and I do not use mail to receive nor send emails.

I am not sure, in my case, spool directly connects with "at"

Last edited by yjcong (2014-03-01 07:51:01)

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#4 2014-03-01 09:35:09

yjcong
Member
Registered: 2009-07-06
Posts: 59

Re: [SOLVED]"at" does not work anymore

Thanks DaveCode.

I figure out the reason. It is not spool, but as you said " smells  disk I/O with errors".  I used bleachbit to clean /, and pressed Ctrl-C before it finished. so there is a huge folder in /root which eats up all of free space.

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#5 2014-03-01 23:53:45

DaveCode
Member
Registered: 2008-08-15
Posts: 103

Re: [SOLVED]"at" does not work anymore

Glad things worked out. Disk-full scenarios can glitch many things.

I am a little bit confused

By default nothing lives in /etc/tmpfiles.d but you add new confs there.

I am not sure, in my case, spool directly connects with "at"

Then inspect the bottom of the at package file list. The daemon needs its stuff extant to start properly. Anything in tmpfs disappears at shutdown so that stuff needs to be remade at boot. Here's how:

man tmpfiles.d

Your root disk is ext4 journaled. I recommend a full backup then reformatting without ext4 journal. From a boot CD you can use something like

mkfs.ext4 -v -t ext4 -i 8192 -O ^has_journal -L MyRootDiskName -U fb94e9da-143a-4682-816f-259eb1daf22f /dev/disk/by-uuid/fb94e9da-143a-4682-816f-259eb1daf22f

Tweak other ext4 defaults inside /etc/mke2fs.conf as you may please. (Meaning the one on the boot CD.)

If you're having disk issues then putting some items in tmpfs as shown may help alleviate them. You will also get faster system performance.

Last edited by DaveCode (2014-03-01 23:55:48)

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#6 2014-03-04 11:31:39

yjcong
Member
Registered: 2009-07-06
Posts: 59

Re: [SOLVED]"at" does not work anymore

DaveCode wrote:

Your root disk is ext4 journaled. I recommend a full backup then reformatting without ext4 journal. From a boot CD you can use something like

mkfs.ext4 -v -t ext4 -i 8192 -O ^has_journal -L MyRootDiskName -U fb94e9da-143a-4682-816f-259eb1daf22f /dev/disk/by-uuid/fb94e9da-143a-4682-816f-259eb1daf22f

Tweak other ext4 defaults inside /etc/mke2fs.conf as you may please. (Meaning the one on the boot CD.)

If you're having disk issues then putting some items in tmpfs as shown may help alleviate them. You will also get faster system performance.

Thanks for your recommendation. I will put it in my TODO list wink

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#7 2014-03-04 11:45:42

falconindy
Developer
From: New York, USA
Registered: 2009-10-22
Posts: 4,111
Website

Re: [SOLVED]"at" does not work anymore

DaveCode wrote:

Your root disk is ext4 journaled. I recommend a full backup then reformatting without ext4 journal.

This is really strange advice, even perhaps dangerous, without any qualification.

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