Windows Server - exchange fragmentation issue.

Asked By Joe Letter

11-Sep-07 07:00 PM

I am reposting this as a new issue since the first try didn't work and for
some reason I think my buried post is not getting any replies :)  I hope
this isn't bad etiquette....

I am getting this error on an _sbs 2000_ server.

Event Type: Warning
Event Source: MSExchangeIS
Event Category: Performance
Event ID: 9582
Date:  8/15/2007
Time:  12:34:40 PM
User:  N/A
Computer: NETSERVER
Description:
The virtual memory necessary to run your Exchange server is fragmented in
such a way that performance may be affected. It is highly recommended that
you restart all Exchange services to correct this issue.

So.... I followed the instructions at:
1) http://support.microsoft.com/kb/315407
and at:
2)
http://eventid.net/display.asp?eventid=9582&eventno=2234&source=MSExchangeIS&phase=1

In _particular_ I changed the HeapDeCommitFreeBlockThreshold setting to
262144 at
_unfortunately_  I still have an issue.

It almost seems to me this all happened about the time I added more memory
to the server... we are running about 3 gigs right now.

Can anyone offer any further advice??

Thank you so much,
Puzzled,
Joe.

13-Sep-07 06:31 AM

says...

One thing I do, is always (on all Win machines) set the max and min to
the same (ie set the min to the max).  I figure if it blows out past the
min, then well, it won't get fragmented.

--
Duncan

13-Sep-07 02:15 PM

reference please Cris, I do not believe this to be so.

Delete them both, (set to no paging file)
Reboot
The max usuable pagefile in a standard windows server is 4GB...no matter how
you split it.

13-Sep-07 06:15 PM

Cris, it's SBS2000.

Windows 2000 can use a max of 4095MB per PF but can use multiple PF's
exceeding this value. Joe's page file on C: should be 3GB+~12MB to allow a
dump.

Joe, do you have the /3GB switch in boot.ini, if so, remove it, it is not to
be used on a DC.

On an unmodified SBS2000 the HeapDecommitFreeBlockThreshold is 0. I am not
aware of any reason this should be changed on SBS2000. Joe, you seem to be
implementing 'general' Exchange fixes to SBS, this is not recommended.
Exchange on SBS has been 'tuned' by SBS Dev to compensate for the fact that
SBS disregards several MS 'best practices'.

well apparently some things when SP1 came out that I missed
http://support.microsoft.com/kb/237740/en-us

However, you can create a single page file that is more than 4,095 MB on a
Microsoft Windows Server 2003 Service Pack 1 (SP1)-based computer.

Notes To create a larger page file, you must load the Physical Address
Extension (PAE) kernel. In Windows Server 2003, PAE is automatically enabled
when the server is using Hot Add Memory devices. Alternatively, you can
force the PAE kernel by adding the /PAE switch in the Boot.ini file.

but doesn't /PAE cause its own issues in SBS??

--
Cris Hanna [SBS-MVP]
-------------------------------------------------
Microsoft MVPs
Independent Experts (MVPs do not work for MS)
Real World Answers
---------------------------------------------------------
Please do not contact me directly regarding issues

reference please Cris, I do not believe this to be so.

Delete them both, (set to no paging file)
Reboot
The max usuable pagefile in a standard windows server is 4GB...no matter
how
you split it.

19-Sep-07 05:45 PM

Ok. Thanks..

So, I just changed HeapDecommitFreeBlockThreshold back to 0

here is my boot.ini:

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(2)\WINNT
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WINNT="Microsoft Windows 2000 Server"
/fastdetect

Did you want me to remove the pagefile on E?
Should I set the max and min to 3084 on C only?
(btw. general tab of system proprties says I have 3,145,072Kb Ram.)
Do I really have to reboot the server once without a pagefile, then set one?
Couldn't I just change it and reboot?

Thanks so so much!

19-Sep-07 10:53 PM

I would probably move as much as I could off C: then set the page file to 0
on C: and defrag C:. I would then creat a pagefile on C: at ~3200MB (min and
max). This should result in a contiguous pagefile of sufficient size to
allow a dump, should it be necessary. Moving what you can off C: and
defragging (particularly if you use third party defrag which also moves
files to outer cylinders) allows the pagefile to locate as far out to the
edge as possible, improving performance.

Then move what you want back to C:.

Then do similar for E:, keeping in mind that Windows performs best when the
paging file is only slightly bigger than necessary. There is an area of
which I'm unsure concerning the size of pagefile on additional partitions,
you see, Windows also uses an algorithm to decide which pagefile is going to
offer best performance. For these reasons I'd probably FORMAT E: (umm backup
what's on it 1st :-) and immediately create a 2GB (max and min) pagefile on
E:.

This would result in a pagefile (combined) 5GB, a little over the 'rule of
thumb' of 1.5 times RAM. Both segments would be contiguous blocks, and as
optimally placed as possible.

01-Oct-07 06:43 PM

Well,  Perhaps it would be good to clarify that C and E are on the same
drives in a RAID 5 array.

Does this change any of the recommendation?

At this point I don't care about performance, I just want to stop getting
the exchange fragmentation error.  Also, I don't think the client will pay
for my time to perform the good-to-do-but-not-absolutely-needed process of
formating, defragging, etc.

Any Suggestions?

Thanks!
Joe.

01-Oct-07 07:25 PM

OK, so let's forget all this piffle about the page file and get back to the
original question.

Event ID: 9582
Description:
The virtual memory necessary to run your Exchange server is fragmented in
such a way that performance may be affected. It is highly recommended that
you restart all Exchange services to correct this issue.

A couple of people have raised this recently and my initial reaction was
something along the lines of 'no, haven't seen it', but stories change :-) I
now have one site where I can confirm similar but so far no complaint and
another site I will check today who were complaining about slow email
thurs/fri (tues today, yesterday a public holiday). Both sites are running
stores just under 16GB, I'd be interested to know how big your store is
(size of priv1.edb+priv1.stm).

So, so far I don't know the cause nor the solution. We need to be careful
though about what we do, as mentioned previously Exchange on SBS is a
special beast. See what you can dig up and I'm interested to hear what
actual impact you may notice (does email get slow? does Exchange eventually
fail?).

12-Nov-07 01:15 PM

They are very close to the 16gb...  Actually they hit it, then I had them
delete a bunch of mail.  They are now under 16gb by a few gigs, but they
file edb and stm files remain at the combined size of about 16gb.

They do seem to have what I would classify as minor performance issues... an
occasional "waiting for echange server" at the client side.  It never fails.
The performance, if I remeber right, was about the same before I started
noticing the errors.  In other words, they may not be related.

Maybe I should offline flatten the db?

Thanks!
Joe.

26-Nov-07 04:11 PM

anybody?

26-Nov-07 08:43 PM

If you are close to the 16gb limit, and the users have deleted emails, doing
an offline defrag will help immensely, especially if you have never done one
before.

just make sure that you have enough free disk space on the same partition
where your exchange db is located. In this case, if your store is coming
close to 16gb, then you need approx 18gb (110%) of avaialble space for the
offline defrag.

and, if you have never performed an offline defrag of exchange, this blog's
for you:
http://msmvps.com/blogs/kwsupport/archive/2006/08/26/109871.aspx

--
Kevin Weilbacher [SBS MVP]
*

07-Dec-07 07:21 PM

Kevin,
Thanks!!   I will have to find some time to do that and to report
back here what I find.   I have not done an offline defrag before.  I will
look at that log.

Thanks!
Joe.

07-Dec-07 07:25 PM

Kevin,
Which version of sbs does the instructions at the link you supplied
apply to?  I am using sbs2k on the server in question.

Thanks!
Joe.

07-Dec-07 10:16 PM

The offline defrag work similary for SBS2000 or SBS2003 (that is, Exchange
2000 or Exchange 2003).
http://support.microsoft.com/default.aspx/kb/328804

--
Kevin Weilbacher [SBS MVP]
*