HP XP20000XP24000 Disk Array - Manual (Page 18)

You need to change the SVP (Web server) to Apache, which supports SSL, in order to perform
SSL-encrypted communication. Your HP service representative will change the SVP to the SSL-supported
Apache.
Important Terms and Concepts
The Remote Web Console user should be familiar with the following terms and concepts:
• Disk controller frame. The storage system has one disk controller frame that controls all data
access and storage operations. The storage system provides up to 256 logical control units (CUs)
and supports 3990-6, 3990-6E, 2105-F20, 2107, and open-systems controller emulation types.
For storage system program products, 255 CUs are available at the maximum.
Note: The 3990-3 and 2105-E20 controller emulation types are not supported.
• Logical disk controller frame (LDKC). The storage system controls CUs in groups of 256. This
group is called a logical disk controller frame (LDKC). There is one LDKC for the storage system
and the LDKC is numbered 0.
One LDKC controls up to 256 CUs; however, only 255 CUs are available for the storage system
program products. Therefore, up to 65,280 volumes are available for the storage system program
products.
• 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
information 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.
18 About Remote Web Console Operations