The Storage Team Blog about file services and storage features in Windows Server, Windows XP, Windows Vista and Windows 7.
A customer recently asked us to clarify the 1-TB DFS Replication limit described in an earlier post. Shobana Balakrishnan, our DFS Replication program manager, explains:
There are no architectural underpinnings of the 1TB limit – it is merely what we tested. The Jet limits are much larger. The theoretical limit comes from the number of files under a volume scope due to Jet limits and of course recovery times. Theoretically the Jet DB can grow as large as 32 TB and assume ¼ used for ID records -> 8TB. Assuming an ID record is 1KB worst case, that is 8*10^9 files on the volume.
On a practical note, we have tested over 50 million files taking approx 1 TB of disk space. The database in this case was approx 20 GB.
I should also clarify bullet (5): A replication group can contain up to 256 members.
This is actually not a global replication group limit. A replication group can be arbitrarily large scaling to several thousands of members. Each member must however only be connected to at most 256 partners - and actually this translates to bullet (3) where each server should have at most 128 partners (replicating in-and out).
[Updated on 10/5/06 to clarify areas where customers commonly have questions] The most frequent DFS Replication
Just to make sure I am not losing it:
8*10^9 would make it 8 billion files. Is it possible that the Jet database limit is 32GB (not TB), so the ID records occupy 8GB = 8*10^9B, which divided by the size of one record 10^3B, would give expected the 8*10^6= 8 million files?
Two more questions:
1. Where is the 1/4 allocation for ID records coming from?
2. Is there a way to check how full is the Jet database?