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If the amount of pool usage for the P-VOL exceeds 70 percent of the total
capacity of the cache management devices reserved for the P-VOL, you must
reserve another cache management device. You can reserve a maximum of
256 cache management devices for each P-VOL.
Calculating the Thin Image pair capacity for DP pools
When creating a DP pool, you can set the maximum reserved V-VOL capacity
against the pool capacity. For details about the maximum reserved capacity,
see the
Provisioning Guide for Open Systems
.
When storing snapshot data in a DP pool, set the maximum reserved V-VOL
capacity against theDP pool by calculating the V-VOL capacity of a Thin
Image pair (Thin Image pair capacity) using the following formula:
Thin Image pair capacity = Σ↑(P-VOL capacity (MB)
× Number of pairs × 2 ÷ 42 (MB))↑ × 42 (MB) + Σ↑(P-VOL capacity
(MB) × Number of pairs
× 2 ÷ 2,921,688 (MB))↑ × 175,434 (MB)
Decimal places of the value enclosed by arrows (
↑
value
↑
) are rounded up.
As for
Number of pairs
in the formula, allocated pages are not released if you
delete pairs. Because of this, use the maximum number of TI pairs you want
to create in the applicable snapshot tree as
Number of pairs
instead of using
the number of pairs currently created in the applicable snapshot tree.
If a pair or snapshot data is deleted, allocated pages are not released. As a
result, if you delete pairs or snapshot data, the TI pair capacity is not
decreased. To decrease the TI pair capacity by releasing allocated pages, you
must delete all TI pairs and snapshot data created in the applicable snapshot
tree.
The following example illustrates how the TI pair capacity is calculated.
78
Thin Image system and planning requirements
Hitachi Thin Image User Guide for Hitachi Virtual Storage Platform G Series and F Series
Содержание VSP F1500
Страница 124: ...124 Configuring Thin Image Hitachi Thin Image User Guide for Hitachi Virtual Storage Platform G Series and F Series ...
Страница 202: ...202 Troubleshooting Thin Image Hitachi Thin Image User Guide for Hitachi Virtual Storage Platform G Series and F Series ...
Страница 203: ...Troubleshooting Thin Image 203 Hitachi Thin Image User Guide for Hitachi Virtual Storage Platform G Series and F Series ...
Страница 205: ...Troubleshooting Thin Image 205 Hitachi Thin Image User Guide for Hitachi Virtual Storage Platform G Series and F Series ...
Страница 320: ...320 Glossary Hitachi Thin Image User Guide for Hitachi Virtual Storage Platform G Series and F Series ...
Страница 324: ...324 Index Hitachi Thin Image User Guide for Hitachi Virtual Storage Platform G Series and F Series ...
Страница 325: ...Hitachi Thin Image User Guide for Hitachi Virtual Storage Platform G Series and F Series ...