Per-Entity Metadata Working Group

[Nick Roy <>]

This isn't super relevant, but just thought it an interesting convergence of 
related technology.  AD uses multi-master LDAP to replicate its DNS 
information, which does get written to disk (as a Jetblue ISAM database, 
IIRC).

Nick

On 7/27/16, 12:26 PM, 
"
 on behalf of Nick Roy" 
<
 on behalf of 
>
 wrote:

    And every Active Directory Domain Services environment that is correctly 
deployed still does this (caches DNS locally for all the attached nodes), 
which means a chunk of almost every large IT environment with Windows clients 
does this to some extent.
    
    Nick
    
    On 7/27/16, 12:12 PM, 
"
 on behalf of Jorj Bauer" 
<
 on behalf of 
>
 wrote:
    
        >>    Sure, and DNS has the same characteristics.
        >
        > DNS can tolerate long outages? That is really not my experience, 
but I'm no DNS expert. Can you clarify?
        
        The records themselves have a TTL. Caching servers can cache the data 
        until that TTL expires. After that, no - there's no guarantee the 
data 
        would be useful, and it's flushed.
        
        >> It's easy enough to configure a server to use a locally installed 
DNS caching server, and
        >> I would hope to be able to do the same with an MDQ server as an 
intermediate cache.
        >
        > Would you disagree that that would be a very much minority view?
        
        Today's DNS infrastructure is built to be robust and responsive. So 
yes, 
        I agree that most people would not do this today. This was a useful 
        configuration in environments where DNS is problematic, or where the 
DNS 
        latency was too high for throughput, or other sorts of unreliability.
        
        With the beginning of MDQ, I think this architecture would be 
desirable 
        until we have mature infrastructures.
        
        Apologies for having missed the background, and maybe asking 
something 
        that's obvious to everyone else at this point - I have a standing 
        meeting at the time of the weekly calls, unfortunately - but is there 
        any sort of TTL on metadata served by MDQ? As an endpoint, I'd want 
to 
        know how long it is viable for. Which enables various sorts of 
caching.
        
        -- Jorj