zfs over iscsi

[krage]

HI! I'm using zfs over iscsi.

Storage is named "zfs". Backend is running targetcli.

I am having problems with

create full clone of drive scsi0 (vm01:vm-103-disk-0)
TASK ERROR: storage migration failed: Could not open /dev/tank/vm-103-disk-0

This happens most of the time. but sometime, i do not get this error.

Whenever try to move a disk, the datastore is created on the backend server, but targetcli havent made the approriate backstore or lun yet.

If i tried enough times it would eventually be able to move the storage. All the storages on there, is working just fine, but now, it seems like i only get this error and cant create vms or move storages to the zfs storage anymore.


There are absolutely no logs. Just the error above.

How can i debug this?

 

[bbgeek17]

Hi @krage, welcome to the forum.

The error comes from your remote storage node that is running ZFS/iSCSI. Have you examined the logs/state of that node? What is that node?

---

Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

 

[krage]

Thanks for the quick reply reply!
That node is a proxmox server (witness only) running zfs and targetcli.



If i look at the remote storage, i can see in zfs history that the datastore has been created and that /dev/tank/vm-103-disk is available, but has a broken symbolic link to ../../zd208

I dont really understand how this entire thing works, but this is something i need to figure out. Is the remote storage unable to create the blockdevice neccecary for this to work properly ?


The logs are more or less empty. I cant figure out why zd208 is broken.


... so after researching a bit more, i found out I created this udev-rule:

KERNEL=="zd*", SUBSYSTEM=="block", ACTION=="add|change", PROGRAM=="/lib/udev/zvol_id $devnode", SYMLINK+="/%c"

To fix another symlink issue

But that was actually the wrong way of doing it. I wanted /dev/zvol/tank to become a link to /dev/tank - not mess around with the zvol links.
So the above udev rule created erroneous symlinks.
After removing it and reloading using udevadm it started working again.

I had to create a custom service that recreates the symlink /dev/zvol/tank -> /dev/tank at boot.
Hopefully i'll remember the above rule if it turns out it doesnt work after all

so... fixed!