SLES 12 Unable to IPL the system after resizing "/" btrfs filesystem

mikenash · 01-25-2017, 02:55 PM

I have a z/linux SLES12 system built with the btrfs file system.
I successfully add and resize the file system.
When I reboot the system I hit an endless loop on the system with a "start job".

Code:

btrfs device add /dev/dasda /
btrfs filesystem resize max /

A start job is running for dev-disk-by\x2duuid-b2732... 5s

I am able to do this with a system built with the xfs file system.
I am thinking that maybe the device needs to be added to the kernel!?

mikenash · 01-30-2017, 08:47 AM

I have found two methods that work for resizing the btrfs "/" filesystem.
The two methods are to update /etc/fstab or update the kernel and then update grub2.
I have a couple of questions.
1 - When I extend a xfs filesystem I do not need to update the kernel or /etc/fstab.
why is this needed for btrfs?
2 - When I update the kernel I had to specify both disks.
The IPL volume and the dasd the I use to extend the filesystem.
I thought it odd that I had to specify the IPL volume.
Is there a reason for this? The 3120 address is the IPL volume.
Note: this is probably true for updating /etc/fstab but I did not try this variation.

Code:

Method 1: Update /etc/fstab
cio_ignore -r 0.0.0604
chccwdev -e 0.0.0604
lsdasd - check dasd location
dasdfmt -b 4096 -f /dev/dasdb -p -y
fdasd -sa /dev/dasdb
Yast - make device persistent
reboot
btrfs device add /dev/dasda1 /
btrfs filesystem resize max /
Update /etc/fstab
UUID=b273239f-1943-4607-ad44-2e007624ee1b /   btrfs      device=/dev/dasda1,device=/dev/dasdb3 0 0
grub2-install

Method 2: Update the kernel.
cio_ignore -r 0.0.0604
chccwdev -e 0.0.0604
lsdasd - check dasd location
dasdfmt -b 4096 -f /dev/dasdb -p -y
fdasd -sa /dev/dasdb
Yast - make device persistent
reboot
btrfs device add /dev/dasda1 /
btrfs filesystem resize max /
Yast update kernel parameters - !0.0.0604,!0.0.3120 and dasd=0604,3120
grub2-install