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Tape Capacity Calculations
Tape Capacity Calculations
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Capacity Planning Chart
Server, Amount of Data, Full Frequency (days), Retention (days), Incremental
Frequency (days), Retention (days), Percentage of Change, Required Storage
SIZE = INPUT
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Full = TotalData ( DaysToRetainFull / DaysBetweenScheduledJobs)
Differential = PercentChange * TotalData * DaysToRetainIncr \
( 1 - ( 1 / DaysBetweenScheduledJobs))
Cumulative = PercentChange * TotalData * DaysBetweenScheduledJobs \
* DaysToRetainIncr \
((1/DaysBetweenScheduledJobs ) - (1/DaysBetweenScheduledJobs))
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How much tape do you need
DLTtape.com gives some practical formulas to assist companies in determining
how much tape they need depending, of course, on the tape capacity your
company has standardized on.
TAPES FOR STORAGE
Xs = D * T * S * R + N
Xs = number of tapes per year for storage
D = number of backup drives
T = number of tapes in the media set
S = number of sets in rotation
R = number of rotation schedules per year
TAPES FOR ARCHIVE
Xa = T * S * A
Xa = number of tapes per year for archiving
T = number of tapes required to copy each server
S = number of servers
A = number of archive sets per year
TAPES FOR DISASTER RECOVERY
Xr = T * S * R
Xr = number of tapes per year for recovery
T = number of tapes per server (from above)
S = number of servers (from above)
R = number of disaster recovery sets required
TOTAL ANNUAL TAPE REQUIREMENTS
X = Xs + Xa + Xr + R
X = total number of tapes per year
Xs = number of tapes per year for storage (from above)
Xa = number of tapes per year for archiving (from above)
Xr = number of tapes per year for recovery (from above)
R = number of new replacements for tapes retired
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