I'm not confused. ;-)
cndilip123 provided more detail on what I was saying.
Whe you create a Distributor AW you can also make it an HDS (Historical Data Store), which is an optional step. If you call this box an AW it is confusing - you should call it an AW/HDS to make it clear.
There is no such thing as an "HDS" on its own, but there can be AWs that don't act as an HDS - that means they have no HDS database, and no ICM replication processes to pull data from the Logger and insert into the HDS database.
Real time data is not purged - it's just overwritten with new data. This is computed as a rolling 5 minute window. Real-time data is not in the HDS.
When you look at the Views of an AW database carefully, you will notice that some of these are referring to data that is actually in the HDS.
For example, you might run a select on the AWDB for the Agent_Half_Hour data and get some data back - but the data is not surely in the AW. That's not a table, it's a view and it's a view into the HDS:
CREATE VIEW Agent_Half_Hour AS SELECT t.* FROM lab_hds.dbo.Agent_Half_Hour t
Study the Schema Help for more info.
Regards,
Geoff