WARNING: This English version is translated by AI from the Chinese version.

After reviewing other tutorials, I found that most require operations within DSM. I’ll take a different approach and perform the operations directly in PVE.

First, power down the virtual machine.

1. Required Packages

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apt update
apt install mdadm parted

2. Disk Expansion

Start by expanding the disk through the GUI interface, then open the Shell. Since I’m using zvol with a zpool named rp_01, the block device is located at /dev/zvol/rp_01/vm-200-disk-0, and the corresponding data partition (the third partition) is vm-200-disk-0-part3. Use the parted tool to expand the partition:

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parted /dev/zvol/rp_01/vm-200-disk-0 resizepart 3 100%

3. Partition Expansion

Begin by expanding the RAID array:

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mdadm --assemble --update=devicesize /dev/md2 /dev/zvol/rp_01/vm-200-disk-0-part3
mdadm --grow /dev/md2 --size=max

Next, mount the LVM volume. Start with a scan:

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vgscan

Then proceed with mounting. My volume group is named vg1 and the storage volume is volume_1 - adjust these names according to your setup:

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vgchange -ay vg1
mkdir -p /mnt/tmp_mount
mount -t btrfs /dev/vg1/volume_1 /mnt/tmp_mount

Perform the expansion:

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btrfs filesystem resize max /mnt/tmp_mount

4. Unmounting from PVE

Execute the following commands:

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umount /mnt/tmp_mount
vgchange -an vg1
mdadm --stop /dev/md2

You can now start DSM, but the process isn’t complete yet. Once DSM boots up, open the Storage Manager application. It will prompt you to expand the storage - simply accept the prompt.

Finally, here’s a crucial step! Remove the mdadm package. If you don’t, PVE will automatically mount any detected RAID arrays on the next boot, which will cause kernel crashes and DSM failures:

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apt autoremove mdadm
dpkg -P mdadm

The expansion process is now complete.

References:

https://xpenology.com/forum/topic/66292-virtual-disk-info/

https://xpenology.com/forum/topic/17105-expandresize-btrfs-syno-volume-after-disk-space-increased-esxi-hyper-v/