Exchange database increased by 4X

[hbkn]

I have just upgraded my Exchange 5.5 on a NT 4.0 system to Exchange 2003 on a Win2003 system. The private information store file was approximately 3.8 Gb on the 5.5 system, but now it is 16 Gb on the 2003 system. I have 700 users, and when I add the mailbox sizes for the users it is 3.3 Gb.
Can anyone tell me, what's happened?
The problem is that I've met the limit of 16.3 Gb in the standard edition and the database unmounts.

 

[AndyPeck]

Your left with few choices,
1. offline the store and defrag the white space.

http://support.microsoft.com/default.aspx?scid=kb;en-us;192185&Product=exch2003

2. Set quotas on users
3. Then start working of the finance department to sign off for an upgrade to the Enterprise version, but you done well to grow the system to 700 users on standard edition, you must run a pretty tight ship already.

 

[hbkn]

Thanks for your answer. I upgraded to Enterprise version today and it worked. But my question was not so much about what to do, rather why the database files increased by a factor 4 while converting from Exchange 5.5 to Exchange 2003.
I've done the defragging with eseutil /d but it only decreased the private store about 0.5 Gb.

 

[johnny99]

When we migrated from 5.5 to 2003 we did a mailbox-by-mailbox migration and we also ended up with a lot more data then we started out with.
We went from around 50 GB in 5.5 to around 80GB in 2003.

The extra data came mostly from attachments because every single attachment was migrated to every single relevant users mailbox.

Normaly when you send an email with an attachment to a lot of users Exchange only stores one copy per database, but because of the mailbox migration this ends up with a seperate copy in each mailbox.

/johnny

 

[FromTheHip]

What Johnny99 said is correct. In 5.5, there was one copy of every e-mail stored in the Database and pointers that told each mailbox where to lool. In 2k and 2k3, there is one copy of each message saved per storage group, as well as one message per store.

So if you have 2 SG and 2 stores/SG and sent a message to all of your users, you would have had one copy with a lot of pointers in 5.5, but in 2k and 2k3 you have 6!! 5x increase in store size can be expected, and there are actually tables you can use to guesstimate what your final size will be.