When you create a new Protection Group using the “Create Protection Group” wizard, DPM internally computes and allocates volumes for storing the replica and the shadow copies. This blog post enumerates the various formulae that we use internally to generate the default size.
File system datasource
SC size = (dataSourceSize * recoveryRangeInDays * 2) / 100 + 1 GB;
Replica size = (dataSourceSize * 3) / 2;
SQL DB
Replica size = dataSourceSize * (1 + LogChange) / (AlertThreshold - .05);
SC size = 2.5 * recoveryRangeInDays * LogChange * dataSourceSize + 1 GB
Exchange SG
replicasize = dataSourceSize * (1 + LogChange) / (AlertThreshold - .05);
SCSize = 4.0 * recoveryRangeInDays * LogChange * dataSourceSize + 1GB
where
Log change = 0.06
Alertthreshold = 0.9
