Hello RobertKo,

1.       Yes you can as long as you are using 17 or more disk.  Here is a link to a Dell EMC Unity Family Configuring Pools & if you look on page 42 it shows that you can.

1.https://dell.to/3dAUd0W

The spare drive policy follows these rules to determine how many drives are left as

spares:

l In general, the system reserves one spare drive for every group of 1-31 drives that have the same type, capacity, and rotational speed (or Flash type). For example, if there are 40 300-GB, 15K-RPM SAS drives in the system, the system reserves two of those drives as spares.

2.       The Unity 680f can support a max of 1000 drives.  Here is a link to Dell EMC Unity XT Introduction to the Platform & if you look on page 10 & 11 it list out the max number of drives for each system. https://dell.to/32C2Phy

3.       You can see how to expand pools on page 15 of this link. https://dell.to/3dAUd0W

since each of the two builtin SAS ports support max 10 DAE / 250 drives it requires a 4-port 12Gb SAS Backend I/O Module to connect more than 500 disks

question 3 - no

there is no way around the hotspare policy or to disable it.
the system will reserve the min amount of spares or in case of dynamic pools spare space

Hello,

Thank you for answer.

Yes, I know that according to the data sheet the Unity XT 680 supports expansion up to 1000 drives. But is it possible if all expansion slots are already occupied by Fibre Channel cards? Each controller then has only two SAS ports.

Robert Kolaczynski

Hello RobertKo,

If all expansion slots are filled then the max drives you can have is 500.