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mdadm eating up CPU with no I/O load

Offline jwmw

mdadm eating up CPU with no I/O load
« on: July 28, 2018, 03:23:07 PM »
Hi everyone,

at my parents home I have an SME Server with a recent quadcore and 8 GB of RAM. Since a month everytime I look into top the process mdadm is taking ~ 95% CPU

I restarted the process but after a few minutes the same picture :-(

The raid itself is healthy. A reboot and installing all updates didn't help.

Any thoughts??
« Last Edit: July 28, 2018, 03:25:16 PM by jwmw »

Re: mdadm eating up CPU with no I/O load
« Reply #1 on: July 30, 2018, 01:37:28 AM »
I remember something about a raid test, an automatic procedure, I think it started at 4:00 AM (but not sure)...
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Offline jwmw

Re: mdadm eating up CPU with no I/O load
« Reply #2 on: July 30, 2018, 11:05:23 AM »
Thanks Fumetto,

for that hint. Unfortunatly this process occupies one thread 24/7  :shock: :???: not sure what mdadm does whole the time.

Offline craig

Re: mdadm eating up CPU with no I/O load
« Reply #3 on: July 31, 2018, 05:27:05 PM »
Is there any disc activity?

Offline ReetP

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Re: mdadm eating up CPU with no I/O load
« Reply #4 on: July 31, 2018, 06:09:04 PM »
Not sure why it is firing itself like this.

Have you done any mods to the server at all?

I guess first have a look in /etc/cron.d

There should be a file called raid-check

[root@home etc]# cat /etc/cron.d/raid-check
# Run system wide raid-check once a week on Sunday at 1am by default
0 1 * * Sun root /usr/sbin/raid-check

What do these show?

Code: [Select]
cat /proc/mdstat
Code: [Select]
cat/etc/mdadm.conf

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Offline Jean-Philippe Pialasse

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Re: mdadm eating up CPU with no I/O load
« Reply #5 on: August 15, 2018, 10:01:02 PM »
check your disks with smartctl short and long test (or any already logged errors), you might have a defective disk.
I saw this few months ago, and it happened to be a drive about to die.