More information about FAST

Hi!

I am very interested in the FAST technology and I would like to understand much better how does it work. In the VMAX product guide there is an example in page 90 but I can't understand it. There are 3 tiers:

• 1 TB Flash
• 3TB FC
• 5TB SATA

The first tier (the flash), is assigned 50% of 1TB storage group, 50% of 2 TB storage group and 20% of a 2TB storage group. Therefore: 0.5TB+1TB+0.4TB=1.9TB which is greater than the 1TB Flash which was deployed!

1 - What am I misunderstanding?

2 - The policy applied to the last storage group is 25% to the tier 2 and 100% to the tier 3. What does this mean? 25% of the storage will go to the tier 2 and in case there is no space, it would go to the tier 3?

Apart from answering my questions, it would be great if someone culd suggest me a link to some doument where FAST is well explained in a Symmetrix environment.

Thanks,