Issue/Introduction

This article describes how to troubleshoot a VM instance on local storage that repeatedly restarts but cannot start. It applies to the initial diagnosis and resolution of similar issues in ZStack Cloud.

Environment

• Product: ZCF
• Component: Cloud
• Version: 3.x-5.5.30

Resolution

Try the following methods:

• The VM instance may fail to start because the host has insufficient CPU, memory, or network IP resources. Use the error information to determine whether the host lacks any of these resources.
• For local storage, also check XFS file fragmentation as follows:

1. Log in to the VM instance operating system and run xfs_db -c frag -r /dev/XXX to check fragmentation on each disk. If the output is actual 93133, ideal 8251, fragmentation factor 91.14%, you can run xfs_fsr /dev/XXX to defragment XFS.

XXX is the disk device name, such as vda1.

2. If severe disk fragmentation causes a deadlock and the VM instance hangs, you can restart the host to resolve the deadlock.