IBM DS8700, Introduction And Planning Manual

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the AS/400 operating system does not perform software mirroring on the LUN.
The selection of protected or unprotected does not affect the RAID protection that
is used by DS8000 on the open volume. In either case, the volume remains
protected by RAID.
On CKD volumes, you can specify an exact cylinder count or a DS8000 standard
volume size to create a LUN. The DS8000 standard volume size is expressed as an
exact number of Mod 1 equivalents (which is 1113 cylinders). The unit of storage
allocation for CKD volumes is one CKD extent. The extent size for CKD volume is
exactly a Mod 1 equivalent (which is 1113 cylinders). Any logical volume that is
not an exact multiple of 1113 cylinders (1 extent) does not use all the capacity in
the last extent that is allocated to the logical volume. For CKD volumes that are
created with 3380 track formats, the number of cylinders (or extents) is limited to
either 2226 (1 extent) or 3339 (2 extents). For CKD volumes that are created with
3390 track formats, you can specify the number of cylinders in the range of 1 -
65520 (x'0001' - x'FFF0') in increments of one cylinder, or as an integral multiple of
1113 cylinders between 65,667 - 262,668 (x'10083' - x'4020C') cylinders (59 - 236
Mod1 equivalents). Alternatively, for 3390 track formats, you can specify Mod 1
equivalents in the range of 1-236.
Note: On IBM i, the supported logical volume sizes for load source units (LSUs)
are 17.54 GB, 35.16 GB, 70.56 GB, and 141.1 GB. Logical volume sizes of 8.59
and 282.2 GB are not supported.
Table 5 provides models of storage capacity and disk volumes for System i.
Table 5. Capacity and models of disk volumes for System i
Model
Number
(Unprotected) Model
Number
(Protected)
Capacity
Expected
Number
of LBAs OS
Version
Support
A81 A01 8.59 GB 16 777 216
(0x01000000) Version 5 Release 2 and
Version 5 Release 3
A82 A02 17.55 GB 34 275 328
(0x020B0000) Version 5 Release 2 and
Version 5 Release 3
A85 A05 35.17 GB 68 681 728
(0x04180000) Version 5 Release 2 and
Version 5 Release 3
A84 A04 70.56 GB 137 822 208
(0x08370000) Version 5 Release 2 and
Version 5 Release 3
A86 A06 141.12 GB 275 644 416
(0x106E0000) Version 5 Release 3
and later
A87 A07 282.25 GB 551 288 832
(0x20DC0000) Version 5 Release 3
and later
Extended address volumes for CKD
Count key data (CKD) volumes now support the additional capacity of 1 TB. The 1
TB capacity is an increase in volume size from the previous 223 GB.
This increased volume capacity is referred to as extended address volumes (EAV)
and is supported by the 3390 Model A. Use a maximum size volume of up to
1,182,006 cylinders for the IBM zOS. This support is available to you for the z/OS
version 12.1, and later.
You can now create a 1 TB IBM System z CKD volume on the DS8700 and DS8800.
Chapter 2. Hardware and features
39