HP StorageWorks XP Remote Web Console Software - Manual (Page 22)

• Disk array frame. The disk array frame of the storage system contains the storage components
(hard disk drive arrays).
• Parity group. A parity group (also called array group) is a set of hard disk drives that are treated
as one group. For example, a RAID-5 3D+1P parity group consists of four disk drives (3 data
and 1 parity). A parity group contains both user data and parity information, and the parity in-
formation is used to automatically reconstruct the user data if one of the disk drives in the parity
group becomes unavailable.
• LDEV (logical device). The storage system supports a maximum of 65,536 LDEVs. However, up to
65,280 volumes are available for the storage system program products.
An LDEV can be called a volume. An LDEV used by mainframe hosts can be called a device or
logical volume image (LVI). An LDEV used by open-system hosts can be called a device (for example,
SCSI disk device, raw device) or a logical unit (LU).
NOTE:
Only up to 32,640 LDEVs are available for some of the storage system functions or program
products.
• LU (logical unit). An LDEV used by open-system hosts is called an LU. An open-system LU on the
Fibre Channel interface can be mapped to one or more LDEVs.
• CU (control unit). The storage system supports a maximum of 256 logical CUs numbered sequentially
from 00-FF. Each CU controls up to 256 LDEVs. LDEVs within the storage system are accessed by
a combination of CU number (00-FF) and device number (00-FF).
However, the CU number FF is reserved for the HP StorageWorks XP RAID Manager operation.
Therefore, the CUs that can be used for the storage system program products operation are up to
CU number FE. This means that the number of CUs that can be used for the storage system program
products operation are 255 per LDKC at the maximum.
The following table shows an example of the device numbers for CU.
Table 5 Example of Device Numbers for Each CU
Possible
Device
Numbers
CU
Number
Possible
Device
Numbers
CU
Number
Possible
Device
Numbers
CU
Number
Possible
Device
Numbers
CU
Number
30:00 to
30:FF
30
20:00 to
20:FF
20
10:00 to
10:FF
10
0:00 to
0:FF
0
31:00 to
31:FF
31
21:00 to
21:FF
21
11:00 to
11:FF
11
1:00 to
1:FF
1
32:00 to
32:FF
32
22:00 to
22:FF
22
12:00 to
12:FF
12
2:00 to
2:FF
2
33:00 to
33:FF
33
23:00 to
23:FF
23
13:00 to
13:FF
13
3:00 to
3:FF
3
34:00 to
34:FF
34
24:00 to
24:FF
24
14:00 to
14:FF
14
4:00 to
4:FF
4
35:00 to
35:FF
35
25:00 to
25:FF
25
15:00 to
15:FF
15
5:00 to
5:FF
5
About Remote Web Console Operations 22