Longhorn volume in degraded state with "insufficient storage;precheck new replica failed" error after a node reboot

SUSE Enterprise Storage - Longhorn- 1.7.3

One or more Longhorn volumes fall into a degraded state with the mentioned error, even though the nodes have sufficient storage space. This issue might occur in an environment where the worker node is temporarily shut down or rebooted abruptly. This article outlines the known bug and a possible workaround to mitigate the error to bring the volumes back to a healthy state. 

• The following error is observed for the degraded volumes in the Longhorn UI:

Replica Scheduling Failure
Error Message: disks are unavailable;insufficient storage;precheck new replica failed

• It is also observed that the nodes have enough disk space available to schedule replicas. 
• Upon further investigation, the longhorn-manager pod shows below error:

2025-08-11T07:01:23.729057940Z time="2025-08-11T07:01:23Z" level=info msg="Cannot find a reusable failed replicas for volume pvc-xxxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxx" func="scheduler.(*Repli
caScheduler).CheckAndReuseFailedReplica" file="replica_scheduler.go:635"

• This is a known issue as explained here: 10210. The issue is fixed in the Longhorn version 1.8.0 and above. 
• The following workaround can be implemented to resolve the issue:
  • Go to Longhorn UI >> Volumes >> Select the affected Volume >> Click on the Hamburger icon and enable “Replica Disk Soft Anti-Affinity”

• When the Longhorn node is rebooted or shut down abruptly, the replica may become faulty, and Longhorn will try to rebuild the replica on a healthy node. However, the bug mentioned above prevents the rebuild and marks the volume as degraded. 
• The workaround of enabling Disk‑level soft anti‑affinity ensures that Longhorn allows scheduling the replica correctly on any healthy node.