To know Occupied size of individual site collection in SharePoint

Use STSADM.EXE
syntax:-
stsadm -o enumsites -url http://xxxxx/ >test.txt

Example:-
stsadm -o enumsites -url http://mysitecollection/ > test.txt

this will write all site collections occupied size in MB's into a text file.

so how it look like...

<Sites Count="1">
  <Site
    Url="http://url"
    Owner="A\user"
    SecondaryOwner="A\user2"
    ContentDatabase="WSS_Content_DB"
    StorageUsedMB="13756"
    StorageWarningMB="0"
    StorageMaxMB="0" /> </Sites>

check it.....

cheer
JK