Netbackup Appliances MSDP pool Capacity

Hi All,

I need to know how do we calculate the required disk space for customers that how much cpacity of MSDP pool they needed to manage their backup environment. 

Actually I am facing difficulties with few customers, where MSDP pool is getting full. Now I wanted to analyze and setup SLPs with different retentions so that MSDP disk pool wont get full. Most of the customers requirement are to keep the first copy with 2 weeks retention on disk and then duplicate it to tape with AIR replication.

Kindly help me with any tool and calculated formula for MSDP pools on Symantec Appliances 5220, 5230.

Thank you for your help.

Regards,

Priyeranjan