Snapshot And Tce Capacity - Hitachi AMS2100 User Manual

NOTE: A portion of cache memory is assigned to SnapShot for internal
operations. For more information, please see
with Cache Partition

SnapShot and TCE capacity

2-32
Hitachi AMS 2000 Family Copy-on-Write SnapShot User Guide
•
Manager.
When TCE is used, SnapShot and TCE share common data pool
resources. Therefore, you calculate their managed capacities
together. If TCE is not used, you only calculate SnapShot's capacity.
All formulas, tables, graphs and examples pertain to one controller.
On dual controller arrays, you must perform calculations for both
controllers.
Managed capacity is calculated here, per controller, using the
following formula:
Size all SnapShot P-VOLs +
Size of all TCE P-VOLs (if used) +
Size of all TCE S-VOLs (if used) +
/ 5
+ size of all data pool volumes
< Maximum Supported Capacity
Maximum supported capacity is shown in
•
Table 2-14: Maximum Supported Capacities, Cache Size
Cache Memory
per Controller
2 GB per CTL 1.4 TB
4 GB per CTL 6.2 TB
8 GB per CTL Not supported
16 GB per CTL Not supported
Example:
To calculate capacity when only SnapShot is used
In this example, the array and cache memory per controller is
AMS 2300/4 GB.
1. List the size of each P-VOL in the Storage system. For example:
P-VOL 1 = 100 GB
P-VOL 2 = 50 GB
2. Calculate managed P-VOL capacity, using the formula:
ROUNDUP (P-VOL capacity / 15.75) * 15.75
For example:
Planning and design
Appendix D, Using SnapShot
Table
per Controller
(SnapShot P-VOLs,
TCE P-VOLs, S-VOLs, Data Pools)
AMS2100 AMS2300
Not supported
6.2 TB
12.0 TB
Not supported
2-14.
AMS2500
Not supported
Not supported
12.0 TB
24.0 TB