DFS replication and SIS

[RW]

here is our situation:
- multiple File Servers in defferent geo location set to use DFS, content is
replicated 100%
- 3 x 2 TB volumes on each server with dozen of shares, again shares, map
drives, in all geo locations are exactly the same, these servers for easy
mgmt are almost like clone of each other to keep it simple, same volume size
same drives , same shares
- now we are enabling SIS on all servers

Here are areas on concerns:
1. since SIS Common store is not part of DFS replication and I think .sis
files are are not replicating anyways in DFS what exactly happens with
changes?
i.e. there is file a file called file1.xls which has duplicates SIS will
store this file in SIS common store and keep link files in orginal location,
since we use 100% DFS replication these duplicated file also exist on other
file servers in other geo ocations, again SIS on those other servers will put
file1.xls into local SIS common store and kept link files on orginal
locations
question what happens when one of these files will change? I'm guessing
those files are no longer duplicates since there was a change in one of them,
will file1.xls modified be removed from SIS common store and moved to orginal
location? what happens to duplicate file? will this also be removed and put
into original location?
will all this changes recognized by other servers participating in DFS
replication?

[DaveMills]

Post by RW
- multiple File Servers in defferent geo location set to use DFS, content is
replicated 100%
- 3 x 2 TB volumes on each server with dozen of shares, again shares, map
drives, in all geo locations are exactly the same, these servers for easy
mgmt are almost like clone of each other to keep it simple, same volume size
same drives , same shares
- now we are enabling SIS on all servers
1. since SIS Common store is not part of DFS replication and I think .sis
files are are not replicating anyways in DFS what exactly happens with
changes?
i.e. there is file a file called file1.xls which has duplicates SIS will
store this file in SIS common store and keep link files in orginal location,
since we use 100% DFS replication these duplicated file also exist on other
file servers in other geo ocations, again SIS on those other servers will put
file1.xls into local SIS common store and kept link files on orginal
locations
question what happens when one of these files will change? I'm guessing
those files are no longer duplicates since there was a change in one of them,
will file1.xls modified be removed from SIS common store and moved to orginal
location? what happens to duplicate file? will this also be removed and put
into original location?
will all this changes recognized by other servers participating in DFS
replication?

I would be more concerned with the replication of the Link file. Say on server 1
SIS creates a link pointing to SISCommonStore\targetA and on server 2 the link
is pointed to SISCommonStore\targetB. What happens during DFS replication? Will
the link to TargetA replace the link to TargetB on server 2 and screw up the SIS
system or will the SIS links be followed and the real content in SISCommonStore
be the replication content. I do not know but if it is the former then you will
quickly get into data loss. I do know that implementing R2 Quotas will get you
into trouble if you get near to the quota limits so maybe this will too. I would
not be surprised if DFS replicated the link and not the target. After all that
is what it must do for SYSVOL. Equally if you think about such constructs as the
"User/Documents and Settings" items in Vista/W7 which use Links you would not
expect to end up with two copies being replicated but one copy and the link.

You need to do some careful testing.