HP StorageWorks XP24000 for FlashCopy Mirroring Software User's Guide (T5240-96001, June 2007)
the conditions you need to consider when calculating the numb er of Version 1 relationships that can be
created. Use the following expression to calculate the total number of differential tables per relationship:
Total number of the differential tables per relationship = ↑((X)+(Y))×15÷(Z)↑
(X): The number of cylinders in the volume.
(Y): The numbe
r
of control cylinders (see Table 28 on page 56).
(Z): 20,448 (t
he
number of slots that can be managed by a differential table).
↑:Round up the
number.
Note that you should round up the number to the nearest whole number. For example, in the case
of a volume with emulation type 3390-3, if the number of cylinders in the divided volume is 3,390
((X) in the ex
pression above), the calculation of the total number of differential tables is as follows:
(3,339+6)×15÷20,448= 2.4537...
When you round up 2.453 7 to the nearest whole number , it becomes 3. Therefore, the total
number of dif
ferential tables for o ne relationship is three when the emulation type is 3390-3.
You may use 36 differential tables per pair table. The total number of pair tables is one when the
emulation type is 3390-3. For example, in the case of a volume with emulation type 3390-M, if
the
number of
cylinders in the volume is the default value, the number of pair tables is 2. However,
emulation type 3390-M can only be used if you use multiple pair tables on the mainframe system.
• Conditions for the number of pairs that you can create
Maximum num
ber of relationships that satisfies Σ(α) ≤ (β)
and
Maximum number of relationships that satisfies Σ(γ) ≤ (δ).
• Σ(α) stands for the total number of differential tables per relationship.
• (β)standsf
or the
number of differential tables available in the storage system.
• Σ(γ) stands for the total number of pair tables per relationship.
•(δ) stands for the number of pair tables available in the storage system.
(β)and (δ) will differ according to the installed additional shared memory. For details, see
Table 10 on
page 24.
For exampl
e, if you create 10 relationships of 3390-3 and 20 relationships of 3390-L in a storage
system for
which no additional shared m emory for differential tables and pair tables is installed,
the
total number of differential tables per relationship will be as follows:
• Σ(α) : (3 x 10) + (24 x 20) = 510
The total n
umber
of pair tables per relationship will be as follows:
• Σ(γ): (1x10)+(1x20)=30
Since 510 ≤ 26,17 6 and 30 ≤ 8,192istrue, youcan create allthe relationshipsthatyou
want to cr
eate.
Cautions on Turning Off the Power While Using Version 1
If you have to switch off the power supply for the storage system during Version 1 operations, make sure
to complete the backgrou n d copying operation for the Version 1 relationship, and then switch off the
power supply. If you turn off the power before the background copying operation is completed, the
shared memory may be volatilized when you switch on the power supply again, and the Version 1
relationship will be released and the T-VOL will be blocked.
Installing and Uninstalling Version 1
This section describes how to install and uninstall Version 1.
For det
ails about
the license operation, see the HP StorageWorks XP24000 Remote Web Console
User's Guide.
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