My goal is to shrink an mdadm RAID 1 partition while the system is running. I have to disks sda and sdb, which build my two RAID partitions md0 and md1. On md1 I use LVM, md0 is the /boot partition. I already reduced the size of the LVM physical volume (and all its logical volumes/file systems) AND the md1 without a problem. But the actual partitions sda2 and sdb2 are not updated automatically. Can I just fdisk them while the system is running? Maybe reboot afterwards? Will that suffice? Or do I have to take the system offline? Are there other ways to shrink the partitions?

EDIT: I just tried it, it didn't work. After changing the partition sizes, the machine refused to reboot, giving me just a black screen with a blinking line. I changed the partitions back using a Live CD. Now it's booting again. Can anyone tell me what the heck I'm doing wrong?

EDIT 2: By the way, I used mdadm --grow /dev/md1 --size=<smaller size> to reduce the size of md1.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.