Support Tips: HEAT
Today I wanted to dig a little deeper on our new HyperCore Enhanced Automated Tiering(HEAT) feature which includes configurable SSD priority allocation at the individual virtual disk level through an easy-to use slide bar in the HC3 interface, and intelligent data block priority based on block I/O heat mapping assessed utilizing historical I/O information on each virtual disk.
By default, a new virtual disk will automatically get assigned a SSD priority of 4 on a scale of 0 to 11. The scale, represented by the slide bar in the HC3 interface, is exponential, meaning that changing the priority of a VM virtual disk from 4 to 5 in the management UI doubles the priority of that data for SSD placement. This scaling means that even one position change on the slide bar can provide significant performance improvement and requires less experimenting with various settings.
The values of 0 and 11 on the slide bar are unique. A setting of 0 eliminates SSD storage usage on that virtual disk (convenient for a static FTP drive, for example). 11 changes the SSD priority by an order of magnitude, multiplying the priority of the virtual disk data for SSD placement by 10. When you turn it to 11, you really crank it.
Due to the nature of HEAT it will automatically put the most accessed or "hot" blocks to the ssd storage and move less accessed or "cold" blocks to spinning disks. This means leaving all disks at 4 will provide a balanced and significant performance benefit to all disks equally, but you have the freedom to increase or decrease the priority based on your specific needs.
Support is always available if you need guidance or have questions about the best way to prioritize your disks on your HC3 system.