Mount a volume at boot

Mount cetrafs read-write or as a read-only observer, by hand, from /etc/fstab, or with a systemd mount unit.

Mount by hand

Read-write, as a full cluster participant:

sudo mount -t cetrafs /dev/sdb /mnt/cetra

As a read-only observer, to inspect a live volume from another host without taking write capacity or replaying anything:

sudo mount -t cetrafs -o ro /dev/sdb /mnt/cetra

For a Proxmox/qemu cluster that live-migrates VMs, add nofilelock. See Enable live migration.

Mount at boot with /etc/fstab

/dev/mapper/mpatha  /mnt/cetra  cetrafs  _netdev,nofail  0  0

• _netdev waits for the network, which iSCSI needs. It does no harm on Fibre Channel.
• nofail lets the host finish booting if the LUN isn’t there.
• Add nofilelock to the options on a live-migration cluster, and add it on every node.
• Use a stable device name: a multipath alias, or a /dev/disk/by-id/... path. Never a bare /dev/sdX, which can change between boots.

You don’t need to load the module in advance. The first cetrafs mount loads it.

Mount with a systemd unit

If you prefer a unit, name it after the mount path (/mnt/cetra becomes mnt-cetra.mount):

# /etc/systemd/system/mnt-cetra.mount
[Unit]
Description=cetrafs shared datastore
After=network-online.target iscsid.service multipathd.service
Wants=network-online.target

[Mount]
What=/dev/mapper/mpatha
Where=/mnt/cetra
Type=cetrafs
Options=nofilelock

[Install]
WantedBy=multi-user.target

sudo systemctl daemon-reload
sudo systemctl enable --now mnt-cetra.mount

Check the mount

ls /proc/fs/cetrafs/                         # one directory per mounted volume
grep -E 'write_ready|file_lock|fenced' /proc/fs/cetrafs/*/info

Changing mode later

Read-only and read-write participation, and the file-lock mode, are fixed at mount time. mount -o remount,ro and remounts that change nofilelock are refused. Unmount and mount again with the options you want.

If the mount fails

The troubleshooting reference has more.

Last updated 21 October 2026