is this a VNX ? You cant' expand raid groups on VNX, you would have to create a brand new RAID group and utilize Meta functionality.

Refer to EMC KB article emc269369,

Symptom    Cannot expand
a RAID group on the VNX Series.

Cause      The RAID
group expansion feature was removed from VNX OE 05.31.

Fix        An expansion can be done with metaLUNs or Pool LUNs.

yes, you can expand RG with disks from other enclosures, do consider this (from Clariion BP whitepaper) :

Binding with DPE drives

In a total power-fail scenario, the SPS (standby power supply) supplies battery-backed power to the SPs and vault disks. This allows the storage system to save the contents of the write cache to disk.

However, the power to the non-vault disk storage system enclosures (DAEs) is not maintained. When the storage system reboots, LUNs that had I/O outstanding are checked, using the background verify process, to verify that no writes in progress resulted in partial completions. The background verify is a fairly low-intensity process.

However, a LUN bound with some drives in the vault enclosure (DPE or first DAE, depending on the model) and with some drives outside of the vault enclosure may require a rebuild, which is a more disk-intensive process. This affects performance to some degree on reboot.

To avoid a rebuild on boot, create groups with all disks either in or out of the vault enclosure. If groups are split, follow these guidelines:

1. Do not split RAID 1 groups across the vault enclosure and another DAE.

2. For parity RAID (RAID 5, RAID 3), make sure at least two drives are outside the vault enclosure.

3. For RAID 1/0, make sure at least one mirror (both the primary and secondary drive in a pair) is outside the vault enclosure.

EMC Clariion CX4-480  Model

Flare Operating Environment  04.30.000.5.525

Unisphere

no matter if expando RG formed with the following disks:

Bus 0 Enclosure 0

Bus 0 Enclosure 0

Bus 0 Enclosure 0

-----------------------------------

And I add a disk "Unbound"

Bus 1 Enclosure 2

No need to be the same Bus and the same Enclosure, to expand a RG?

what is the capacity of disks in the RG you are trying to expand ? Same capacity/speed as the unbound disk ?

no

Sorry, but why my SG will be grow only ~250G ? I have a "Unbound" disk that Capacity si 536 GB.

It can cause a problem, that the capacities are different?

I´s not the same capacity:

Disk from RG: -> 258.403 Raw Capacity, Model : HUS15303 CLAR300

Unbound  Disks: Raw Capacity: 536.808  Model: HUS15606 CLAR600

it's not a problem, it's just all members of a raid group have to consume the same amount of space ..so the raid group will ignore the fact that this drive has an additional 250G worth of space.