DPM 2007 — Calculating Disk Allocation

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

 

Mukul Singh Shekawat