LUN (VLL) and Volume Shredder User Guide (T5214-96094, November 2011)

The required system disk capacity is as follows:

• Capacity for Quick Format management information: 46 MB, which means 66 cylinders if

the track format is 3380; or NF80, which means 55 cylinders if the track format is 3390.

• Capacity for the audit log buffering area: 130 MB, which means 185 cylinders if the track

format is 3380; or NF80, which means 154 cylinders if the track format is 3390.

• Capacity for additional configuration backup: 7,744 megabytes, which means 9,082 cylinders

if the track format is 3390. The following program products are for the additional configuration

backup function:

◦ XP Business Copy

◦ ShadowImage for Mainframe

◦ XP Auto LUN

◦ HP XP for FlashCopy Mirroring Software

◦ HP XP for FlashCopy Mirroring V2 Software

◦ XP Snapshot

◦ XP Thin Provisioning

To use the Quick Format management information, the audit log, and the Additional configuration

Back up function, you must prepare the system disk with the capacity to store that information in

advance. For example, if two system disks that have 35 MB capacity each are prepared, the

backup copy of the Quick Format management information cannot be made into these system

disks. If the system disk is used for multiple purpose, HP recommends that all necessary capacities

are retained in one volume. For example, to store the Quick Format management information and

the audit log in a system disk, your system disk should have 176 megabytes or more of disk

capacity.

The following rules apply when creating system disks:

• Normal data cannot be stored in system disks.

• You can create only 16 volumes for system disks in the entire storage system.

• HP recommends that you create system disks in internal volumes even though you can also

create system disks in external volumes.

• There is no restriction on the emulation type for system disks.

• When a storage system has both open-system volumes and mainframe volumes, choose the

open-system volume over the mainframe volume to create system disks.

• If you create system disks in a mainframe volume, specify the LDKC:CU:LDEV number that is

not configured in the host I/O generation.

• Make sure that the LDKC:CU:LDEV number for a system disk can be distinguished from the

LDKC:CU:LDEV numbers for normal volumes.

• Do not set the bind mode of Cache Residency Manager to a system disk.

• Open-system hosts cannot issue I/Os because the SCSI path cannot be defined for a system

disk. Mainframe system hosts also cannot issue I/Os. CC=3 is returned when an I/O is issued.

• To delete system disks, use the Volume to Space function (see “Converting Logical Volumes

to Space” (page 62)).

If one of the following conditions apply, you might not be able to delete or block a system disk.

Delete or block the system disk when these conditions do not apply.

• The Quick Format operation is being performed.

• It has been 20 minutes or less since the Quick Format operation completed.

76 Performing Virtual LVI/LUN and Volume Shredder Operations