How is storage assembled correctly?

Question

RAID

I want to understand storage systems, in particular the FAS8060. I can't understand what the numbers in the table mean, for example: The maximum number of disks is 1200 (Where can I put 1200 disks there?); Memory - 120 GB (what kind of memory is this?); Dual controllers in one 6U case (how and why?) and what does UTA ​​2 mean in the phrase "Built-in I / O module: UTA2".
And the same thing for example in DS4246: Is
the number of 4U racks stupidly the size of a shelf or does it mean something else?
The number of drives per module 24 is the max number of drives in the shelf or what?
Number of disks per rack 6 - what is meant by the word "rack"
The only thing I understand so far is that FAS806 is a basket into which these shelves are inserted and from here 2 more questions arise: Is it possible to insert two shelves DS2246 and DS4246 into one such basket? And what to do if this basket runs out of space: Buy a new such "hellish thing" with shelves and stuff it, or you can just buy the necessary shelves and connect through some external interfaces (if 2 is correct, then through which ones)?
PS
I myself have not seen such things in my eyes and probably will not see them, but I want to figure it out

Answer 1

I'll try to answer about netapp. Fas8060 is an expandable system, disk shelf controller, with the ability to work in a cluster configuration.
1200 disks is the maximum number of disks with attached disk racks (jbod).
120gb - internal memory of the disk controller (there is also 18tb nvram memory! - like a giant SSD disk, for caching and / or storage)
Uta2 - universal I / O controller, can work as 10gb ethernet or as 16gb FC. The controller is dual, in fas 8060, if I'm not mistaken, there are 8 such controllers.
The controller is expanded in several ways, by connecting additional jbod disk shelves, interconnecting with a similar fas8xxx system via 40gb infiniband or ethernet / FC, connecting other DHSs using supported protocols.
Several controllers can form a cloud storage cluster.