HP StorageWorks XP Remote Web Console Software - Manual (Page 24)

Example
S2= [{4398046511104 / (256 x 1024)} x (32 / 74784)] x 74784
= 7178.9542... x 74784
= 536874336
S1= 1073741824 536874336 8388608
= 528478880
Total capacity of P-VOLs (kB) = (528478880 / 74784) x 16384 x 256
= 7066.737... x 16384 x 256
= 7067 x 16384 x 256
= 29641146368
Maximum number of XP Snapshot pairs will be as follows:
Maximum number of XP Snapshot pairs = 29641146368 / [ {(10 x 1024 x 1024) / 4194304} x4194304]
= 29641146368 / 12582912
= 2355.666...
= 2355
According to these results, you can create a maximum of ,2,355 XP Snapshot pairs.
If a shared memory is added to your storage subsystem and you know the pool capacity, you can
estimate the capacity of a P-VOL that can be created, as explained in
Table 6 on page 24. To calculate
the actual capacity of a P-VOL that can be created, use the above formulas.
Table 6 Estimate of Capacity to Create a P-VOL
And If the Pool Capacity is If a Shared Memory is Added to
10,240
GB 8,192
GB 6,144
GB 4,096
GB 2,048
GB 1,024
GB
na na na na 10 TB 15 TB Basic XP12000 Disk Array
na na 10 TB 21 TB 32 TB 37 TB
Exten-
sion 1
10 TB 21 TB 32 TB 43 TB 54 TB 59 TB
Exten-
sion 2
32 TB 43 TB 54 TB 65 TB 76 TB 81 TB
Exten-
sion 3
na na na na 3 TB 10 TB XP10000 Disk Array
Using the number of pair tables
Hitachi FlashCopy Mirroring Version 2 and XP Snapshot pairs use pair tables to store control
information needed to manage pairs. To create an Hitachi FlashCopy Mirroring Version 2 or XP
Snapshot pair, you need one pair table for each pair.
Usually, up to 32,768 pair tables are available in one array. However, if the relationship expansion
function, which is an Hitachi FlashCopy Mirroring Version 2 function, is enabled, the maximum number
of available pair tables in one array is 1,048,575.
Among array software products, only Hitachi FlashCopy Mirroring Version 2 and XP Snapshot use
pair tables. Therefore, if you use Hitachi FlashCopy Mirroring Version 2, calculate the number of
Requirements for XP Snapshot operations 24