Inefficient disk usage by OS

[dexter136]

I am not sure if this can be fixed during installation, as I am not very well versed in ansible/rocky/lvm.

I found that the root directory of the nodes is limited to 70GB in size in all nodes I deployed - two with 256GB drives and one with a 512GB drive - and the /home directory is given the majority of the disk space. As longhorn uses the root volume for PVCs this leaves the majority of the disk unusable by longhorn.

I was able to resolve this manually by running the following to recreate the volume for /home with a smaller size and granting the newly available disk space to the root volume.

#Install  xfsdump and backup /home
yum -y install xfsdump
xfsdump -f /tmp/home.dump /home

#Unmount /home and remove the volume
umount /home
lvremove /dev/mapper/<vg name>-home

#Create a new volume for home, limited to 5GB, and restore the backup to it
lvcreate -L 5G -n home <vg name>
mkfs.xfs /dev/mapper/<vg name>-home
mount -a
xfsrestore -f /tmp/home.dump /home

#Extend the root volume to use the newly available space
lvextend -l +100%FREE /dev/<vg name>/root
xfs_growfs /dev/mapper/<vg name>-root

[khuedoan]

Ohhh I didn't notice that, thank you!

Fixed in 0171288, it will not create a /home partition anymore (we don't store anything in there anyway), but you will need to replace the nodes one by one (just added the document in 056e906).

Before:

NAME               MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda                  8:0    0 119.2G  0 disk
├─sda1               8:1    0   600M  0 part /boot/efi
├─sda2               8:2    0     1G  0 part /boot
└─sda3               8:3    0 117.7G  0 part
  ├─rl_metal0-root 253:0    0    70G  0 lvm  /
  ├─rl_metal0-swap 253:1    0   7.9G  0 lvm  [SWAP]
  └─rl_metal0-home 253:2    0  39.8G  0 lvm  /home

After:

NAME               MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda                  8:0    0 119.2G  0 disk
├─sda1               8:1    0   600M  0 part /boot/efi
├─sda2               8:2    0     1G  0 part /boot
└─sda3               8:3    0 117.7G  0 part
  ├─rl_metal3-root 253:0    0    70G  0 lvm  /
  └─rl_metal3-swap 253:1    0   7.9G  0 lvm  [SWAP]

[khuedoan]

Hmmm just realized the root partition is still 70GB even without the /home partition, I'll need to check that.

[khuedoan]

We'll need something more advance like this https://dark.ca/2009/08/03/complex-partitioning-in-kickstart/

However I'm thinking of switching to Rook Ceph for better performance and use a separate partition for data.

[dexter136]

Without the /home partition it is much easier to grow root:

lvextend -l +100%FREE /dev/<vg name>/root
xfs_growfs /dev/mapper/<vg name>-root

That feels like something that can be automated.

[khuedoan]

Fully fixed in bce3291:

• Remove LVM
• Create boot (0.5GiB) and root (remaining) partitions manually instead of using automatic partitioning

root@all (4)[f:5]$ lsblk
metal0 | CHANGED | rc=0 >>
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 119.2G  0 disk
├─sda1   8:1    0   512M  0 part /boot/efi
└─sda2   8:2    0 118.8G  0 part /
metal1 | CHANGED | rc=0 >>
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 119.2G  0 disk
├─sda1   8:1    0   512M  0 part /boot/efi
└─sda2   8:2    0 118.8G  0 part /
metal2 | CHANGED | rc=0 >>
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 119.2G  0 disk
├─sda1   8:1    0   512M  0 part /boot/efi
└─sda2   8:2    0 118.8G  0 part /
metal3 | CHANGED | rc=0 >>
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 119.2G  0 disk
├─sda1   8:1    0   512M  0 part /boot/efi
└─sda2   8:2    0 118.8G  0 part /

This is subject to change since I may switch to Rook Ceph.