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accuracy of Event 1221: online deframentation

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accuracy of Event 1221: online deframentation - 29.Mar.2005 3:07:00 AM

douglas168

Posts: 61
Joined: 4.Mar.2004
From: USA
Status: offline

How accurate is this reported free space by EventID:1221 online defragmentattion?

I am using Standard Exchange Server. Even if every mailbox reaches it storage limit, I calculated it to go up to 11GB. EventID:1221 says I have only 814MB left.

On our test server, I have 3 mailboxes with a total of about 1GB. Yet, its EventID:1221 says it only has 512MB free space.

How can accurately tell how much free space I have left?

Also, if I edit the registry to temporary increase by 1GB, is the EventID:1221 reporting 16GB minus storage or 17GB minus storage?

appreciate the help,
Douglas

Post #: 1

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RE: accuracy of Event 1221: online deframentation - 29.Mar.2005 6:49:00 AM

Velocat

Posts: 574
Joined: 6.Jan.2004
From: Tucson, AZ
Status: offline

Hi douglas168,

This event is telling you the database file has 814Mb of white space _within_ the database itself. It is not reporting that you have 814Mb left on your disk partition nor is it tell you that your database can only expand 814 more Megabytes. The priv.edb file can expand to 16Gb with Exchange Standard Edition.

What does the properties of the drive show you as far as free space is concerned? How big is your priv.edb file?

Sounds like you should be just fine if you review these two items.

Let us know and good luck.

(in reply to douglas168)

Post #: 2

RE: accuracy of Event 1221: online deframentation - 29.Mar.2005 7:10:00 AM

Henrik Walther

Posts: 6848
Joined: 21.Nov.2002
From: Copenhagen, Denmark
Status: offline

Also remember the .STM file isn't included in the calculation of an Event 1221.

(in reply to douglas168)

Post #: 3

RE: accuracy of Event 1221: online deframentation - 29.Mar.2005 1:46:00 PM

Guest

Henrik,

The .stm is not included in the 1221. But does the eseutil /d will defragment .stm ? Or will it just defragment .edb?

Thanks

(in reply to douglas168)

Post #: 4

RE: accuracy of Event 1221: online deframentation - 29.Mar.2005 1:51:00 PM

Henrik Walther

Posts: 6848
Joined: 21.Nov.2002
From: Copenhagen, Denmark
Status: offline

Hi Mike,

Yes an off-line defrag with Eseutil will do both the .EDB and .STM file.

(in reply to douglas168)

Post #: 5

RE: accuracy of Event 1221: online deframentation - 29.Mar.2005 6:42:00 PM

douglas168

Posts: 61
Joined: 4.Mar.2004
From: USA
Status: offline

Thanks Eric,

It has plenty of hard drive.

What is the difference between "814MB of white space_within_the_database" vs. "814MB of database space"?

So, the only way to get an accuracy read on database size is to do a offline defrag?

Douglas

(in reply to douglas168)

Post #: 6

RE: accuracy of Event 1221: online deframentation - 29.Mar.2005 9:32:00 PM

Velocat

Posts: 574
Joined: 6.Jan.2004
From: Tucson, AZ
Status: offline

Hi douglas168,

Databases grow as space is required. Please excuse my elementary description, but I find it to be a useful method to describe the database's growth.

In this example:
paper = email and
the box = the database.

So if you can imagine throwning in a bunch of paper into a box, the box will eventually get full. At this point in order to keep puting in paper, you need a bigger box (therefore the database grows). So now you have a bigger box with paper that's just about filling the box. Then you decide to throw away half of the paper...you now have a box that is much bigger than needed for the paper.

Your database acts the same way, as email is removed from it, a background process defrags the database and reports on the amount of "free-space" within. The database file itself does not ever shrirk. Repeat, the database file does not shrink in size.

In order to shrink the database, you must perform an offline defrag with a utility called ESEUTIL. This must be done with exchange services offline. There is documentation on how to run the tool, and if you decide to do so you should be well aware of what it is doing and how to prepare in case of a failure.

Hope this helps.

(in reply to douglas168)

Post #: 7

RE: accuracy of Event 1221: online deframentation - 30.Mar.2005 2:39:00 AM

douglas168

Posts: 61
Joined: 4.Mar.2004
From: USA
Status: offline

Hi Eric,

I like your comparision. Just to make sure I get this right...

online defrag tells you how much space you have left in current "box".

offline defrag tells you how much space you have left in maximum allowable "box" (16GB).

Is this right?

What I am trying to do is tell the managment...Give the amount of max. storage limits per mailbox, how many mailboxes can the Exchange server hold?

ps, Eric, I am in Sunnyvale, CA also.

Thanks,
Douglas

(in reply to douglas168)

Post #: 8

RE: accuracy of Event 1221: online deframentation - 30.Mar.2005 6:43:00 AM

Exchange_Admin

Posts: 376
Joined: 23.Feb.2003
From: Texas
Status: offline

You stated:
1. "online defrag tells you how much space you have left in current "box".

2. offline defrag tells you how much space you have left in maximum allowable "box" (16GB)."

1. You are correct.
2. The OFFLINE drfrag actually removes the white space in the database, thus reducing the size of the database.

FYI:
Alot of people call it ONLINE DEFRAG. Actually it is Online Maintenance. Exchange parses throught the database and removes tombstoned object that have expired and marks this space as reusable.
A tombstoned object for example may be a message. If you have deleted item retention configured for lets say 7 days, then exchange mark this message with a tombstone when it is deleted. Then when online maintenance runs all the tombstones are checked. If they have expired (in this case 7 days have passed) then Exchange will mark this space as reusable in the database.

To learn more about this process, read the following:
Exchange 2000 information store maintenance and online defragmentation

(in reply to douglas168)

Post #: 9

RE: accuracy of Event 1221: online deframentation - 30.Mar.2005 5:43:00 PM

Velocat

Posts: 574
Joined: 6.Jan.2004
From: Tucson, AZ
Status: offline

Hi douglas168,

I found a nice artlice on this site regarding Exchange database disk consumption here:
http://www.msexchange.org/articles/Exchange-Databases-Disk-Consumption.html

Review the parts about Recoverable Items which are governed by the Deletion settings on the database (how long deleted items and deleted mailboxes are kept).

Also, you may want to review this one to see how
Single Instance Storage can help with database size, (and how mailbox moves affect Single Instance Storage)
http://support.microsoft.com/kb/175481

Sunnvale too huh...I'm looking forward to some sunshine and warm weather this week!

(in reply to douglas168)

Post #: 10