Planning and Design 2–7
Hitachi Simple Modular Storage Copy-on-Write SnapShot User’s Guide
b. Press Enter.
This instructs the tool to calculate the average value in cells B2
through B7 and populates C4 with that data.
c. Copy the value in C4.
d. Highlight cells C5 to the last C cell in the last row of workload data in
the spreadsheet.
e. Right-click the highlighted cells and select the paste option.
Excel maintains the logic and increments the formula values initially
entered in C4. It then calculates all the point in time averages and
populates the C cells.
Figure 2-5 illustrates rolling averages graphed over raw
measurement data averages.
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Figure 2-5: Rolling Averages Graphed Over Raw Averages
4. Locate the maximum rolling average (RA) value in the C column. Using
this peak value and the following formula, calculate the cumulative peak
data change over the lifespan of a copy (V-VOL):
(RA peak MB/sec) x (V-VOL lifespan seconds) = (Cumulative data over V-VOL lifespan)
For example, if the RA peak is 25 MB/sec, and the V-VOL lifespan is 3600
seconds (1 hour), then:
25MB/sec x 3600 seconds = 90,000 MB
The cumulative data over a V-VOL’s 1-hour lifespan is 90,000 MB.