Proxmox: resize an iSCSI-backed LVM

Space can only be increased, not reduced.

Same setup as our other Proxmox iSCSI posts: two paths (110 and 111), interfaces iscsi-110 and iscsi-111, TrueNAS as the target. Grow the LUN on TrueNAS first, then follow these steps.

Find the WWID and volume group

pvs -o pv_name,vg_name

Find current iSCSI sessions

cat /sys/class/iscsi_session/session*/targetname | sort -u

On all nodes‍


# check current size
lsblk -o NAME,SIZE,TYPE,MOUNTPOINT
# rescan the iscsi session to pick up the new size
iscsiadm -m node -T <target_iqn> --rescan
# confirm block devices picked up the new size
lsblk -o NAME,SIZE,TYPE,MOUNTPOINT
# resize the multipath device to match
multipathd resize map <wwid>
# confirm mpath shows the new size
lsblk -o NAME,SIZE,TYPE,MOUNTPOINT

On a single node

# resize the physical volume (use the multipath device, not /dev/sdX)
pvresize /dev/mapper/<wwid>
# confirm the VG has the new free space
vgs

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