Re: Urgent advice requested re: Exchange 5.5 Online/Offline defrag

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From: Al Mulnick (amulnick_No_SPAM_at_ncDOTrr.com)
Date: 06/12/04 

Date: Sat, 12 Jun 2004 10:00:12 -0400

Actually, the online defrag is good. However, in your case I hardly think
it's worth it. You didn't follow all of the advice which mentions that the
database has x amount of free space after online defrag etc. If you had
seen that part, it would have indicated that off-line defrag wouldn't have
bought you much in the way of space recovery.

It's likely that after you remove the data from the store, you'll have some
time before that space gets reused. That's what Exchange does. It reuses
the space where data used to be (called white space). What happens is that
the data blob stays the same size, but won't grow until the store needs the
room. It will first use the white space and then expand the store.

What I'm getting at, is that due to the time and risk of off-line defrag in
your situation, consider cleaning out the items as you say (mailbox
manager?), and buying yourself some time to get another solution in place.
Consider a monitoring solution as well if this is the same path you head
down later. Defrag and database work is time consuming and may end up
costing more than buying Enterprise server version or trying to convert to
some other mailer.

Al

"Help" <anonym@whoknowswhere.osh> wrote in message
news:40caecd9$0$4588$db0fefd9@news.zen.co.uk...
> Hi,
>
> I hope this is a good newsgroup to put an advice request for Exchange 5.5.
>
> We are running Exchange 5.5 Standard edition on an Win2000 server.
>
> Last week it hit the 16GB limit for the private information store. There
> were not warning messages but that's something I'll deal with after the
> recovery.
>
> Following the advice on microsoft site, I decided to do an offline
> deframentation using eseutil.
>
> As I don't have a spare 18GB on the server (the disk is only 32GB) I had
> to use a network drive to store the temporarily created edb file.
>
> I started eseutil defrag at about 8pm on Thursday and at 4pm Friday it
> reached the 100% defrag and started to copy the file back from the
> network drive. So that was about 20hours for the defrag.
>
> The new size of the file is about 15.7GB so I have hardly any space to
> play with and it looks like the defrag hasn't bought me much.
>
> There is no percent complete on the copy of the file back and so I don't
> know how long it will take to copy. It is underway at the moment. I
> looked at the performance stats for the process eseutil and it is
> writing about 140k bytes/second. Scaling that up to 15.7GB and it will
> take about 33 hours to complete the copy. That makes a time for the
> offline defrag about 48 hours.
>
> When that completes, I plan to start exchange IM but without the
> incoming mail started and violently remove old mail/sent mail etcetcetc
> to strip the required information in the store.
>
> After that, to actually reduce the file size, I would need to do another
> offline defrag .. taking me to the end of Tuesday before mail is back.
>
> My question is, how good is the online defrag ? If I clear out enough
> mail so that the mail boxes are, say, 6GB smaller than now, how good is
> the online defrag at freeing up that space ?
>
> I have seen comments saying it is good and some saying it is bad.
> Exchange 5.5 ssems to have mixed comments.
>
> I am assuming that, because there hadn't been an offline defrag for a
> while, and the offline defrag is only pulling back 200MB, that the
> online defrag must have been doing a reasonable job.
>
> I have the options of adding a local disk and doing the offline defrag
> with that, but I am a bit nervous that the actual defrag took 20 hours
> and the copy back looks like taking 32 hours which implies that the
> bottleneck is on my exchange server rather than the network time. (The
> server is a dell poweredge 2200).
>
> I think I am going to have to risk the online defrag but I would
> appreciate advice and suggestions from anyone .. and any ways of
> mitigating the situation.
>
> Also any advice as to my assumptions in the calculations above ..
> whether they are sensible or not...
>
> Once this exciting few days is over, I shall be revisiting the whole
> strategy ... but for the moment, I need to think of the recovery and
> getting my users back up and working by Monday.
>
>
> Thanks for any advice.
>
> Yours
>
> An admin having a peaceful week !
>
>

Relevant Pages

  • Re: Urgent advice requested re: Exchange 5.5 Online/Offline defrag
    ... Offline defrag with temp file on the network is supposed to be long ... P.S. Online defrag after SP2 is quite good at consolidating white space. ...
    (microsoft.public.exchange.admin)
  • Re: Automatic vs offline defrag
    ... at the end of an online defrag reporting the amount of free space within the ... An offline defrag has never been necessary in any version of exchange. ... is in progress on that store. ...
    (microsoft.public.exchange.admin)
  • Re: DEFRAGMENTER
    ... it's not bad advice. ... my opinion is that it is not ideal to ... NTFS should first read http://www.aumha.org/a/ntfscvt.htm because there's ... what happens when you try to defrag C:? ...
    (microsoft.public.windowsxp.help_and_support)
  • Urgent advice requested re: Exchange 5.5 Online/Offline defrag
    ... I hope this is a good newsgroup to put an advice request for Exchange 5.5. ... I started eseutil defrag at about 8pm on Thursday and at 4pm Friday it ... offline defrag about 48 hours. ...
    (microsoft.public.exchange.admin)
  • Re: Datbase Size Understanding
    ... mailbox retention isn't set to zero either. ... should I do an offline defrag again after they are set to zero? ... I did the offline defrag last night at midnight. ... at 2AM the online defrag took effect and this is what it says ...
    (microsoft.public.exchange.misc)