Growing (really grow) a raid1 (mdadm --grow)

didiw · 01-02-2011, 05:38 AM

Hi,

I need to increase a RAID1. I followed a post in another forum which told the following actions:

do a backup
remove on of the raid devices from the raid (mdadm -f ...; mdadm -r ...)
increase the partition with the removed raid device
add it again to the raid
wait till syncing is finished
repeat steps 2-5 for the other device
remove the write-intent bitmap (mdadm -G /dev/mdX --bitmap=none)
mdadm -G /dev/mdX --size=max
mdadm --wait /dev/mdX
mdadm -G /dev/mdX --bitmap=internal

Everything works until step 8. If I do a mdadm --detail /dev/mdX after it, the raid1 still has the same size as before.
What is wrong in that?
I even did that under a rescue system, because the raid1 is where my real /usr is. From reading about growing a raid 1 I got the impression, that it should be doable even in a running system.

Thank you for your answers.

Best regards and a happy new year

Dieter

gb2312 · 01-20-2011, 05:39 PM

I did similar steps (without disk repartitioning --- raid was using only part of the disk initially)
and it worked. Might be because raid/md module doesn't know the partition size changed.

* What's the error after step 8?
* Have you tried --size=NUMBER?
* Could you restart the raid before step 8?