- Maximum capacity of a single external volume is 59.99 TB (128,849,011,200 blocks).
- You can use a volume with more than 59.99 TB, but you can only access 59.99 TB as a mapped external volume.
- Use Virtual LVI/Virtual LUN to create multiple LDEVs of OPEN-V up to the maximum LDEV size of 3.99 TB each. By comparison, 2.99 TB is the maximum capacity of an internal LDEV for all VSP and most of the earlier enterprise models.
For more information about external storage specifications, see HM800 UVM guide (link).
To interpret the above a little:
External capacity is not directly presented to servers (LUNs), used to create pools (POOL-VOLS), or be migrated to another storage type (as LUNS). You must create LDEVs instead. As previously mentioned, LDEVs created directly from external capacity are limited in size to 3.99 TB. Virtual LVI/Virtual LUN may be used to create multiple LDEVs of OPEN-V up to the maximum LDEV size of 3.99 TB each. This allows up to 59.99 TB of a single external device to be used, but not as a single LDEV.
A single 59.9-TB external device may be placed into an HDP pool or an HDT pool, where DP-VOLs of up to 59.99 TB may then be created. However, this will mean that the external volume is effectively formatted before its use.
If you have a single active volume on external storage with capacity exceeding 3.99 TB, you can migrate it to VSP G series [Is "VSP G series" an internal name?] storage without formatting it. Because this process is complex and costly process, professional service is nearly required. When evaluated, few customers chose to adopt this route; but it is available and approved. The capacity must be migrated, not left externalized. Only pools like an HDP pool or an HDT pool support LDEVs of this size.