I ran into an issue at customer where the SSD which is to be used as the cache disk on the VSAN disk group was showing up as regular HDD. However when I reviewed the storage device the disk is visible and is marked as flash…weird. So what is going on here.
As I found out this due to a flash device being used with a controller that does not support JBOD.
To fix this I had to create a RAID 0 virtual disk for the SSD. If you have a Dell controller this means you have to set the mode to RAID but make sure that all your regular HDDs to be used in the disk group is set to non-raid! Once host is back online you have to go and mark the SSD drive as flash. This is the little “F” icon in the disk devices.
This environment was configured with all the necessary VSAN prerequisites for Dell in place, you can review this on the following blog post:
Steps to setup RAID-0 on SSD through lifecycle controller:
- Lifecycle Controller
- System Setup
- Advanced hardware configuration
- device settings
- Select controller (PERC)
- Physical disk management
- Select SSD
- From drop down select “convert to Raid capable”
- Go back to home screen
- Select hardware configuration
- Configuration wizard
- Select RAID configuration
- Select controller
- Select Disk to convert from HBA to RAID (if required)
- Select RAID-0
- Select Physical disks (SSD in this case)
- Select Disk attribute and name Virtual Disk.
- Select ESXi host
- Manage -> Storage -> Storage adapters
- Select vmhba0 from PERC controller
- Select the SSD disk
- Click on the “F” icon above.