Cache Limitations On Data And Data Pool Volumes - Hitachi AMS2100 User Manual

Cache limitations on Data and Data Pool volumes

NOTE: "Data volumes" in this section consist of SnapShot P-VOLs, and
TCE P-VOLs and S-VOLs (if used).
Hitachi AMS 2000 Family Copy-on-Write SnapShot User Guide
• Reduce ShadowImage P-VOL/S-VOL sizes
This section provides comparisons in capacity between the data
volumes and the data pool volumes under the limitations of the AMS
controllers' cache memory. The values in the tables and graph in this
section are calculated from the formulas and maximum supported
capacity in SnapShot and TCE capacity on page
•
•
Table 2-19: P-VOL to Data Pool Capacity Ratio on AMS
2100 when Cache Memory is 2 GB per CTL
Ratio All P-VOL Capacity
to All Data Pool Capacity
1:0.5
1:1
1:3
•
Table 2-20: P-VOL to Data Pool Capacity Ratio on
AMS 2100/2300 when Cache Memory is 4 GB per CTL
Ratio of All P-VOL Capacity
to All Data Pool Capacity
AMS 2100/2300
1:0.5
1:1
1:3
•
Table 2-21: P-VOL to Data Pool Capacity Ratio on
AMS 2300/2500 when Cache Memory is 8 GB per CTL
Ratio of All P-VOL Capacity
to All Data Pool Capacity
1:0.5
1:1
1:3
Planning and design
2-32.
All P-VOL Capacity
to All Data Pool Capacity (TB)
2.0 : 1.0
1.1 : 1.1
0.4 : 1.2
All P-VOL Capacity
to All Data Pool Capacity
(TB)
AMS 2100/2300
8.8 : 4.4
5.1 : 5.1
1.9 : 5.7
All P-VOL Capacity
to All Data Pool Capacity
(TB)
17.1 : 8.5
10.0 : 10.0
3.7 : 11.1
2-39