HP XP7 Storage - Manual (Page 28)

Table 4 Data and journal volume specifications
Support specifications Type
Journal volume Data volume
Unavailable Available Virtual LVI volume
Unavailable Available Cache Residency Z volume
Unavailable 0.964GB 3390-1 Maximum volume
capacity
Unavailable 1.892GB 3390-2
Unavailable 2.838GB 3390-3
Unavailable 8.510GB 3390-9
Unavailable 223.25GB 3390-A
Unavailable 27.80GB 3390-L
Unavailable 55.60GB 3390-M
Capacity of OPEN-V volumes can be
determined freely, and has dependencies on
Virtual LVI volume specifications. Cannot be used as data
volume. OPEN-V
1.5 GB for an OPEN-V volume. 1 cylinder Minimum volume capacity
Duplicating VOLSERs
When the P-VOL is copied to the S-VOL during the initial copy operation, the P-VOL VOLSER (volume
serial number) is also copied to the S-VOL. Therefore, the P-VOL and S-VOL have the same VOLSER.
Because the host operating system does not allow duplicate VOLSERs, the host system administrator
must take precautions to prevent system problems related to duplicate VOLSERs (such as defining
S-VOLs not to come online automatically).
If the volumes that become S-VOLs are physically attached to the same system images as the
volumes that become the P-VOLs, the potential for error increases. For example, when a pair is
released, the old S-VOL is usually offline. When a host system is IPL’d (initial program loaded), the
operator is offered both volumes and asked which volume should be left offline. To avoid duplication
of the VOLSER:
1.
Identify the volumes that are not accessed by the host system.
2. Perform CHP OFF or some other operation to ensure that the volumes are inaccessible.
3. When performing IPL, make sure to perform LOAD CLEAR.
Maximum number of pairs allowed
You can create up to 65,280 pairs on a XP7 system. The maximum number for your system is
limited by:
1.
The number of cylinders in the volumes, which must be calculated.
2. The number of bitmap areas required for Continuous Access Journal data and journal volumes.
This is calculated using the number of cylinders.
CAUTION: The bitmap areas that are used for Continuous Access Journal Z are also used for
Continuous Access Journal, Continuous Access Synchronous, and Continuous Access Synchronous
Z. If you use Cnt Ac-J Z with any of these products, use the total number of each pair’s bitmap
areas to calculate the maximum number of pairs. In addition, if Cnt Ac-J Z and Cnt Ac-S Z share
the same volume, use the total number of both pairs regardless of whether the shared volume is
primary or secondary.
28 Planning volumes, XP7 systems