Linux – Daemon to verify Linux md raid

linuxmdadmsoftware-raid

Is there a way to periodically verify that a linux software raid is valid and has no errors? Like a daemon that would scan all blocks and verify them.

Best Answer

On Debian (and therefore Ubuntu) machines, cron runs:

/usr/share/mdadm/checkarray --cron --all --quiet

the first Sunday of the month. This does exactly what you want.

It basically boils down to:

# echo check > /sys/block/$array/md/sync_action

but with a lot of sanity around it. Steal it from your nearest Debian install, or from the mdadm source package.

Related Solutions

Software MDADM RAID 5 – Inactive MD0 showing

Looks like your drives are all being reported as [S]pares. You should check your logs (dmesg, /var/log/messages) to see if there's any indication why this happened.

Try running the following

sudo mdadm --examine --scan --config=/etc/mdadm/mdadm.conf

And see the output. If it outputs something like this:

ARRAY /dev/md0 level=raid5 metadata=1 num-devices=3 UUID=22f22c3599:613d5231:d407a655:bdeb84 name=backup:1

Then you can append it to the bottom of the mdadm.conf:

sudo mdadm --examine --scan --config=/etc/mdadm/mdadm.conf >> /etc/mdadm/mdadm.conf

Then try starting the array:

sudo mdadm -A /dev/md0

Good luck.

Linux – How to interrupt software raid resync

If your array is md0 then echo "idle" > /sys/block/md0/md/sync_action

'idle' will stop an active resync/recovery etc. There is no guarantee that another resync/recovery may not be automatically started again, though some event will be needed to trigger this.

http://www.mjmwired.net/kernel/Documentation/md.txt#477

Best Answer

Related Solutions

Software MDADM RAID 5 – Inactive MD0 showing

Linux – How to interrupt software raid resync

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