Did you ever run into an unresponsive ESXi hosts? well I did this month and it gave me a lot of headache this past weeks I want to share my finding so others can learn from it and also solve it faster and not to have to restart your hosts and all your VM's. So let me tell a little bit of the environment. The customer had a IBM blade H chassis and 3 HS23 blade each 48 GB. All blades are connecting to a fiber IBM DS3524 and for replication we chose for an iSCSI qnap system to keep it cheap. [...]