@Jonathon Have you rebooted after the update? I should have specified it but the kmod-drbd update is only effective after a reboot.

If the 9.2.16 drbd module was still loaded (i.e. host not rebooted) 16GB would still have been filled quickly with the memory leak unfortunately. 16GB and 9.2.18 should be safe now though.

If unsure you can check the output of modinfo drbd.

Hello,

Indeed this is a known issue with XOSTOR, when causing a sync of too many resources at once it's possible for a DRBD resource to leak memory during the resync. A patch on the 9.2.18 fixes this by throttling the number of resources that can be synced at once to mitigate the issue.

The 9.2.18 update should be in the main xcp-ng-linstor repo very soon.

What you can do too is give more RAM to the dom0 of your hosts. How many RAM have been allocated to dom0 at the moment? We advise 16GB or 32GB depending on the number of volumes.