With DC names like that one should definitely ensure they have a good backup strategy in place.
-----Original Message----- From: Ben Scott [mailto:[email protected]] Sent: Friday, 3 February 2012 9:33 AM To: NT System Admin Issues Subject: Re: Microsoft VM - 5 ways of backing up? On Thu, Feb 2, 2012 at 5:35 PM, David Lum <[email protected]> wrote: >> DR using backed up vhd's is scary with AD, SQL, and Exchange*. >> * Can you say "USN rollback", or "SN rollback", or anything similar? . > > Even with VSS it's scary? My understanding of the problem is: It's not the backup, it's the restore. Every change to AD gets stamped with a USN (Update Sequence Number). Say you've got two DCs, FOO and BAR. Both DCs commit and replicate changes to AD, tracking with their USNs. Say FOO explodes and you restore it to an earlier point in time. Now FOO's USN counter is rolled back to an earlier value, and will start replicating changes using that earlier value. But BAR has *different* changes committed with those *same* USNs, from after the previous backup was done. Duplicate USNs are bad. As in, "Don't cross the streams" bad. -- Ben ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to [email protected] with the body: unsubscribe ntsysadmin ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to [email protected] with the body: unsubscribe ntsysadmin
