Disk space sizing for HDFS/Chukwa

[Kirk True]

Hi all,

It's my understanding (based on the image in 
http://hadoop.apache.org/chukwa/docs/r0.3.0/design.html) that the 
structured data lives in HDFS forever.

When data is migrated from HDFS to MySQL for use in HICC, how does the 
MySQL disk usage compare to the HDFS disk usage? That is, if I'm using 
10 TB of data to store my data in HDFS, what will it be when it moves 
over to HDFS? Is it 2x, 10x, or ???

I'm getting requests for disk size estimates from the IT guys handling 
our staging area and I'm not really sure how to gauge disk usage for MySQL.

Thanks,
Kirk