Garbage collection

  • Thread starter Thread starter Ralph
  • Start date Start date
R

Ralph

In the Directory Service log in Event Viewer, there is the
following event:

Event ID: 1646
Category: Garbage Collection
The Windows Directory Service database has 58 MB of free
space out of 540 MB of allocated space.

This is almost 11% freespace. Are there any
recommendations regarding free space in the AD database?
What's an acceptable or appropriate amount of free space
before an offline defrag should be performed?
 
There's no real rule on this. It is a function of how much stuff has been
deleted and such.

If it is concerning to you, you can free it up by taking the DC offline and
rebooting it in DS restore mode, and do a defrag at that point. In ntdsutil
you can reclaim the free space when in ds restore mode. Note that a defrag
while not in ds restore mode will not reclaim free space, so it is required
you go to that mode first.
When done you should be able to boot back in to normal mode no problem.

Personally, unless your low on disk, I wouldn't worry about it for now. I'd
let it ride, as it isn't doing any harm.

~Eric
 
The only harm could possibly be the time it takes to
search through the database. With that much free space,
there are many holes that must be traversed before the
record is found. With a compacted database, it would take
less time. So the question remains if there are any
recommended levels or percentages. I searched the KB
articles, but found nothing.


-----Original Message-----
There's no real rule on this. It is a function of how much stuff has been
deleted and such.

If it is concerning to you, you can free it up by taking the DC offline and
rebooting it in DS restore mode, and do a defrag at that point. In ntdsutil
you can reclaim the free space when in ds restore mode. Note that a defrag
while not in ds restore mode will not reclaim free space, so it is required
you go to that mode first.
When done you should be able to boot back in to normal mode no problem.

Personally, unless your low on disk, I wouldn't worry about it for now. I'd
let it ride, as it isn't doing any harm.

~Eric

--
Eric Fleischman [MSFT]
Directory Services
This posting is provided "AS IS" with no warranties, and confers no rights


Ralph said:
In the Directory Service log in Event Viewer, there is the
following event:

Event ID: 1646
Category: Garbage Collection
The Windows Directory Service database has 58 MB of free
space out of 540 MB of allocated space.

This is almost 11% freespace. Are there any
recommendations regarding free space in the AD database?
What's an acceptable or appropriate amount of free space
before an offline defrag should be performed?
Click to expand...


.
Click to expand...
 
It would make virtually no difference from a perf perspective. We do online
defrag's every 24 hours (I believe it is 24, but always mess up the # of
hours) so that is keeping the dit organized from a perf perspective. We
just can't clear white space when it is online.

There are no recommended levels. It depends upon your environment, how much
you add/delete, etc.

~Eric

--
Eric Fleischman [MSFT]
Directory Services
This posting is provided "AS IS" with no warranties, and confers no rights


Ralph said:
The only harm could possibly be the time it takes to
search through the database. With that much free space,
there are many holes that must be traversed before the
record is found. With a compacted database, it would take
less time. So the question remains if there are any
recommended levels or percentages. I searched the KB
articles, but found nothing.


-----Original Message-----
There's no real rule on this. It is a function of how much stuff has been
deleted and such.

If it is concerning to you, you can free it up by taking the DC offline and
rebooting it in DS restore mode, and do a defrag at that point. In ntdsutil
you can reclaim the free space when in ds restore mode. Note that a defrag
while not in ds restore mode will not reclaim free space, so it is required
you go to that mode first.
When done you should be able to boot back in to normal mode no problem.

Personally, unless your low on disk, I wouldn't worry about it for now. I'd
let it ride, as it isn't doing any harm.

~Eric

--
Eric Fleischman [MSFT]
Directory Services
This posting is provided "AS IS" with no warranties, and confers no rights


Ralph said:
In the Directory Service log in Event Viewer, there is the
following event:

Event ID: 1646
Category: Garbage Collection
The Windows Directory Service database has 58 MB of free
space out of 540 MB of allocated space.

This is almost 11% freespace. Are there any
recommendations regarding free space in the AD database?
What's an acceptable or appropriate amount of free space
before an offline defrag should be performed?
Click to expand...


.
Click to expand...
Click to expand...
 
circa Thu, 11 Sep 2003 15:48:57 -0500, in
microsoft.public.win2000.active_directory, Eric Fleischman [MSFT]
([email protected]) said,
It would make virtually no difference from a perf perspective. We do online
defrag's every 24 hours (I believe it is 24, but always mess up the # of
hours) so that is keeping the dit organized from a perf perspective. We
just can't clear white space when it is online.
Click to expand...

Every 12 hours by default, IIRC.
There are no recommended levels. It depends upon your environment, how much
you add/delete, etc.
Click to expand...
Ralph didn't believe me when I told him this elsewhere. ;-)

Laura
 
Thanks, 12. I always forget the #.

--
Eric Fleischman [MSFT]
Directory Services
This posting is provided "AS IS" with no warranties, and confers no rights


Laura A. Robinson said:
circa Thu, 11 Sep 2003 15:48:57 -0500, in
microsoft.public.win2000.active_directory, Eric Fleischman [MSFT]
([email protected]) said,
It would make virtually no difference from a perf perspective. We do online
defrag's every 24 hours (I believe it is 24, but always mess up the # of
hours) so that is keeping the dit organized from a perf perspective. We
just can't clear white space when it is online.
Click to expand...

Every 12 hours by default, IIRC.
There are no recommended levels. It depends upon your environment, how much
you add/delete, etc.
Click to expand...
Ralph didn't believe me when I told him this elsewhere. ;-)

Laura
Click to expand...
 
Back
Top