I may get into trouble with this post as
Brett/Eric/Dean/Steve correct me... But that will be good.
I will start with trying to differentiate between
types of corruption... My idea of AD corruption is underlying table corruption.
However some people may consider bad (really unexpected) values in AD to be
corruption. The last isn't corruption, AD is simply a store of data, it passes
no judgement on the data as long as it fits the schema guidelines for the
attribute. If you have the DN of a user in the siteObject attribute that isn't
corruption, it isn't good, but it is valid for the schema. Or if you have binary
data in a unicode string, again, not corruption (a unicode string IS binary
data). That being said, if apps (including parts of AD itself) hit unexpected
data, you will have some issues even if it isn't truly "corruption" it may as
well be in some cases. In fact, table corruption is probably better than
unexpected data in many cases.
You might be able to argue that a USN rollback is
corruption but I still don't consider it so. Valid data, just out of
step.
Again corruption to me is in the underlying tables. Since
AD doesn't replicate the table structures, you can't pass that table corruption
around. Once AD realizes that some portion of the database is corrupt which
would probably be recognized by ESE saying, "that isn't right" and not
passing info back up to higher levels, but instead passing an error.
joe
From:
[EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
On Behalf Of [EMAIL PROTECTED]
Sent: Tuesday, December 06, 2005 3:49 AM
To: ActiveDir@mail.activedir.org
Subject: RE: [ActiveDir] Ntds.dit file corruption
Sent: Tuesday, December 06, 2005 3:49 AM
To: ActiveDir@mail.activedir.org
Subject: RE: [ActiveDir] Ntds.dit file corruption
Is this guaranteed? How can we/you be sure that the system
will recognise the corruptions and therefore not replicate them? Surely this is
akin to the new feature added to e2k3 sp1, but which is (sadly) missing from
AD(?)
I must be missing a subtle point - please show me the light
:)
neil
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Steve Linehan
Sent: 05 December 2005 19:26
To: ActiveDir@mail.activedir.org
Subject: RE: [ActiveDir] Ntds.dit file corruption
We do not replicate corruption so if you have local
corruption as noted below there is no worry that it would replicate around to
other servers in the environment.
Thanks,
-Steve
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Phil Renouf
Sent: Monday, December 05, 2005 1:04 PM
To: ActiveDir@mail.activedir.org
Subject: Re: [ActiveDir] Ntds.dit file corruption
Will Read Only DC's take care of this? I don't know much about them yet,
but it makes sense that if the copy of the dit that a DC has is RO that it won't
try to replicate that anywhere and would only be the recipient of replication.
Anyone with more knowledge about how RO DC's will work to comment on that?
Phil
On 12/5/05, Medeiros,
Jose <[EMAIL PROTECTED]>
wrote:
Well at least the corruption occurred on just a single DC. One thing that has bugged me about Active Directory is not being able to select if you want a DC in a remote office to not have the ability to replicate back in a large enterprise environment. Since most remote offices only have a few people at the location and a DC is usually placed for improvised logon and authentication time, many companies will either use a very low end server or a very old decommissioned one from their production data center ( Which is probably close to useable life ). I am always concerned that once the NTDS.DIT file becomes corrupt it will replicate the corruption to the other DC's in the Forrest.
Maybe I am just being a worry wort and this really is not an issue.
Sincerely,
Jose Medeiros
ADP | National Account Services
ProBusiness Division | Information Services
925.737.7967 | 408-449-6621 CELL
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Susan Bradley,
CPA aka Ebitz - SBS Rocks [MVP]
Sent: Monday, December 05, 2005 8:53 AM
To: ActiveDir@mail.activedir.org
Subject: Re: [ActiveDir] Ntds.dit file corruption
I did? :-) I think I still said all I know is what the poster said :-)
I think I need a course in event log reading because even with the logs,
and the default size of the logs, I still don't see a smoking gun. The
directory services one is filled with events 'post' blow up.
What is interesting is that it seems to me big server land goes .. oh
yeah... ntds.dit corruption... and sbsland freaks out. Either we do
indeed need to ensure we have a secondary DC or we need to park a second
copy of a system state offsite [say at the vap/var]
Brett Shirley wrote:
> She replied offline, very likely a single bit flip, tragedy, they aren't
> one release later (Longhorn), where this would've probably been
> non-disruptively handled, logged, and possibly self-healed:
> http://blogs.technet.com/efleis/archive/2005/01.aspx
>
> Anyway, this kind of thing is usually hardware ...
>
> While there are much better disk sub-system testers, one that is freely
> available to any box with Exchange is jetstress. You might give that a
> try. If you can reproduce the event / error with jetstress I would not
> use that box in production.
>
> If you do reproduce the issue several times (several times is key, as you
> want a trend before you start playing the variable game), some things
> you might vary (one at a time):
>
> - Try making sure you have the latest driver and motherboard / controller
> firmware. Then see if you can reproduce.
>
> - Try a different RAID configuration, such as RAID1/RAID1+0 if you're on
> RAID5.
>
> - Try swapping out the hard drives, one at a time.
>
> - Adding the jetstress files to the exclude list in the Anti-Virus
> software. (A low probablility, I've never heard of Anit-Virus causing this
> paticular type of error, and I can't imagine the mistake an anti-virus
> product would have to have to cause this side effect)
>
> - If you can reproduce it several times, you could followup with Dell.
> Good luck.
>
> I'm not sure if I answered your question ...
>
> Cheers,
> BrettSh
>
>
> On Sun, 4 Dec 2005, Eric Fleischman wrote:
>
>
>> Going back to the original post, I'm not sure I fully understand the
>> problem yet. Susan, can you define "ntds.dit file corruption" for us?
>> What sort of corruption? What errors/events lead you to believe this?
>> Specifically, I'm interested in errors from NTDS ISAM or ESE if you
>> have any.
>>
>>
>>
>> ________________________________
>>
>> From: [EMAIL PROTECTED] on behalf of Susan Bradley, CPA aka Ebitz - SBS Rocks [MVP]
>> Sent: Sat 12/3/2005 10:58 PM
>> To: ActiveDir@mail.activedir.org
>> Subject: [ActiveDir] Ntds.dit file corruption
>>
>>
>>
>> SBS box [with Windows 2003 sp1 since September]
>>
>> RE: [ActiveDir] Database Corruption:
>> http://www.mail-archive.com/activedir@mail.activedir.org/msg32676.html
>>
>> We have a SBS 2003 sp1 box with a corrupt ntds.dit that the Consultant
>> and PSS have been banging on. Could not get the services back running,
>> changed the RPC service to local system and some service came back up [I
>> don't have all the details but the consultant opened a support case of
>> SRX051202605433].
>>
>> Bottom line they are about going to give up and start a restore but
>> before they do that I'd like to get the view of the AD gods and
>> goddesses around here. From all that I've seen, read, seen in the SBS
>> newsgroup, the corruption of ntds.dit is rare to nil and an underlying
>> cause is hardware issues [raid, disk subsystem]. This doesn't just
>> happen.
>>
>> The VAP asked if not properly excluding the ad databases from the a/v
>> would cause this/trigger this and my expectation is 'no', given that I
>> doubt the majority of us in SBSland properly set up exclusions
>> Virus scanning recommendations on a Windows 2000 or on a Windows Server
>> 2003 domain controller:
>> http://support.microsoft.com/default.aspx?scid=kb;en-us;822158
>>
>> If this were my hardware and box, I'd be putting this sucker on the
>> operating table and getting an autopsy before putting it back online.
>>
>> Are we right in being paranoid now about this hardware? For you guys in
>> big server land you'd just slide over another box into that server role.
>>
>> ---------------------------------------
>> Stupid question alert....
>>
>> Okay so we know that having a secondary/additional domain controller is
>> a good thing even in SBSland...but question.... many times the second
>> server in SBSland is a terminal server box because we do not support TS
>> in app mode on our PDCs. So we've established that having a domain
>> controller and a terminal server is a security issue [see Windows
>> Security resource kit, NIST Terminal services hardening guide, etc
>> etc....] If our second server is a member server handing out TS
>> externally, should that be a candidate for the additional DC? Are the
>> issues of TS on a DC ... true for 'any' DC? Would it be better than to
>> Vserver/VPC a Win2k3 inside a workstation in the network if a third
>> server box was not feasible?
>>
>> List info : http://www.activedir.org/List.aspx
>> List FAQ : http://www.activedir.org/ListFAQ.aspx
>> List archive: http://www.mail-archive.com/activedir%40mail.activedir.org/
>>
>>
>>
>>
>
> List info : http://www.activedir.org/List.aspx
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>
>
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